EFFECTS OF SHINNERY OAK CONTROL WITH TEBUTHIURON ON LESSER PRAIRIE-CHICKEN POPULATIONS by CRAIG DONALD OLAWSKY, B.S. in Bio. Sci. A THESIS IN WILDLIFE SCIENCE
Submitted to the Graduate Faculty of Texas Tech University in Partial Fulfillment of the Requirements for I the Degree of I MASTER OF SCIENCE \ \, Approved I" ' i
Chairperson of~tee
Accepted
Graduate School
December, 1987 © 1987 Craig Donald Olawsky ACKNOWLEDGEMENTS
I would like to thank my major advisor, Dr. Loren M.
Smith for his assistance and advice throughout the study. I am grateful for the assistance and helpful suggestions of
Drs. Russell D. Pettit, and M. Kent Rylander, who sacrificed their time to serve on my graduate committee. Sincere appreciation is extended to Dr. David B. Wester for invaluable guidance with statistical analysis.
I wish to thank Paul Gray, Rosemary Heinen, Mike Davin,
Susan Tsai, John Hunter, Dr. Brian Murphy, Tony Leif, Rich
Casner, Denver McMurry, Jay Wipff, Martin Stein, James
Jaspers, G. Allen Rasmussen, Gretchen Scott, Sheila
Merrigan, Colleen Schreiber, Rich Reiner, Mary Candee, Val
Sewell, David Stahlke, Ralph Godfrey, David Cook, David
Price, Bill Wallace, Mark Miller, Tim Riojas, Robert Sites,
David Lee, and Dan Lemkuil, all of whom contributed to the success of the project.
For their friendship, encouragement, and help, I am especially indebted to Perry Grissom, Jim Bergan, David
Haukos, Guy McPherson, Doug Sheeley, and Jeff Weigel.
Financial support for this project was furnished by the
Texas Noxious Brush and Weed Control line item. Dr. Henry
A. Wright also provided financial assistance.
Texas Parks and Wildlife Department, and the New Mexico
Department of Game and Fish supplied permits to collect
ii lesser prairie-chickens. Frequent help was provided throughout this study by several members of the Soil conservation Service. Special thanks are extended to all landowners who graciously allowed the use of their lands for this research, primarily Randy Beasley, who provided the use of field station facilities. Finally, and foremost, I wish to thank my parents,
Donald and Margerine Olawsky for their love, support, and
encouragement. Their faith in me, especially during troubled times, made the completion of this project
possible.
iii TABLE OF CONTENTS
ACKNOWLEDGEMENTS ...... ii
ABSTRACT ...... vi
LIST OF TABLES ...... ix
LIST OF FIGURES ...... xi
CHAPTER
I. EFFECTS OF SHINNERY OAK CONTROL ON LESSER PRAIRIE-CHICKEN DENSITIES...... 1
Introduction ...... 1
Study Area ...... 4
Methods ...... 4
Weather ...... 4
Study Plots ...... 5
Vegetation Composition...... 5
Density Estimates ...... 6
Results ...... •.... 9
Weather ...... 9
Plant Composition...... 9
Density • •••••••• 0 ••••••••••••••••••••••• 13
Discussion · ...... 17
Management Implications...... 21
II. EFFECTS OF SHINNERY OAK CONTROL ON LESSER PRAIRIE-CHICKEN DIET AND GUT MORPHOLOGY ...... 22
Introduction .. , ...... , , ...... 22
Study Area • ••••••••••••••••• 0 •••••••••••••• 24
iv Methods · ...... 24 Results · ...... 27 Precipitation...... 27
Diet ...... 29
Gut Morphology ...... 34
Discussion ...... 37
Conclusions ...... 43
III. NUTRIENT RESERVES OF LESSER PRAIRIE-CHICKENS IN TREATED AND UNTREATED SHINNERY OAK RANGELAND ...... 45
Introduction ...... 45
Study Area ...... 47
Methods · ...... 47 Results · ...... 49 Body Weights ...... 49
Carcass Components and Liver Weights. ... 49
Discussion 59
Conclusions ...... 62
IV. MANAGEMENT RECOMMENDATIONS...... 64
LITERATURE CITED ...... 66
APPENDICES
A. VEGETATION OF THE STUDY AREA...... 72
B. MORPHOLOGICAL MEASUREMENTS OF LESSER PRAIRIE-CHICKENS ...... 78
v ABSTRACT
The herbicide tebuthiuron has been used in recent years to control sand shinnery oak (Quercus havardii) in west
Texas and eastern New Mexico. However, the effects of
shinnery oak control upon lesser prairie-chicken (Tympanllcblls 12allidicinctus) populations are not known. The
range occupied by these birds has decreased over 90% since
the 1800's. Therefore, expanding our knowledge of prairie
chicken requirements and the impacts of various land-use
practices upon the species is a high priority. Without such
information, proper management of these birds is difficult.
To determine the effects of shinnery oak control on lesser
prairie-chickens, we made several comparisons between
tebuthiuron-treated and untreated shinnery oak rangelands
including: (1) vegetation composition, (2) densities of
lesser prairie-chickens, (3) early summer diets and gut
morphology, and (4) body condition of prairie-chickens.
Forb and grass composition was higher in treated plots
than in untreated plots. Densities of lesser prairie
chickens were slightly higher in tebuthiuron-treated sites
than in untreated plots for both seasons. Summer densities
were 0.51 birds/ha in treated plots and 0.41 birds/ha in
untreated plots. Winter densities were 0.53 birds/ha and
0.35 birds/ha in treated and untreated sites, respectively.
vi prairie-chickens were also more difficult to detect in
treated pastures than in untreated shinnery aCrosS seasons.
Foods eaten by lesser prairie-chickens in treated
pastures were different than foods eaten by prairie-chickens
in untreated pastures. Shinnery oak acorns represented the
major portion of the diet for birds collected in untreated
shinnery, but were absent from the diet of birds in treated
areas. Foliage and flowers comprised the majority of foods
eaten in treated plots, but were less important to the diet
of birds in untreated pastures. Prairie-chickens in
untreated shinnery ate more insects than birds in treated
plots during 1984. However, in 1985, insect consumption was
similar between treatments.
Differences in the sizes of digestive organs
corresponded to differences in diet. Small intestines and
caeca were longer in prairie-chickens from tebuthiuron
treated sites than in birds from untreated plots, presumably
because of the increased consumption of foliage.
Conversely, gizzard weights were higher among birds from
untreated shinnery, possibly as a result of greater acorn
consumption in that treatment type.
Lesser prairie-chickens collected from untreated
shinnery had higher lipid levels than birds in treated pastures, indicating that they were in better overall
condition. Higher lipid levels appeared to be correlated with consumption of acorns, seeds, and fruits. Protein
vii levels of prairie-chickens increased from 1984 to 1985.
Higher protein levels corresponded to increased insect consumption. Lesser prairie-chickens could most likely benefit from an interspersion of both tebuthiuron-treated and untreated sand shinnery oak rangeland.
viii LIST OF TABLES
1.1 Monthly precipitation (cm) and deviation from the 3D-year average (cm) for the study area, 1985-1986 ...... 10
1.2 Percent basal composition of vegetation in treated and untreated sand shinnery oak rangelands ...... 11
1.3 Density of lesser prairie-chickens in tebuthiuron-treated and untreated sand shinnery oak rangelands during summer (July-September) 1985 and winter (January-February) 1986 ...... 14
2.1 Monthly precipitation (cm) and deviation from the 3D-year average (cm and percent) for the study area ...... 28
2.2 Food items from lesser prairie-chickens (N=42) collected during summer (27 May-3 July) in tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico ...... 30
2.3 F-values from 2-way analysis of variance (ANOVA) of lengths and weights of digestive tract parts of lesser prairie-chickens collected May-July, 1984-85 from tebuthiuron-treated and untreated sand shinnery oak rangelands...... 35
2.4 Average weights (g) and lengths (cm) of the digestive tracts' of lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands...... 36
3.1 F-values from 2-way analysis of variance (ANOVA) of body weight (BW) , liver weight, and carcass components of male lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands during summer 1984-85 ...... 50
3.2 Comparison of body weight, liver weight, and carcass components (g) of male lesser prairie chickens collected 27 May-3 July, 1984-1985 from tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico ...... 51
ix F-values from 2-way analysis of variance (ANOVA) of body weight (BW), liver weight, and carcass components of female lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands during summer 1984-85 ...... 54
Comparison of body weight, liver weight, and carcass components (g) of female lesser prairie chickens collected 27 May-3 July, 1984-1985 from tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico ...... 55
A.1 Percent basal composition of vegetation on tebuthiuron-treated and untreated sand shinnery oak rangelands during fall 1985 and spring 1986 ...... 73
B.1 Body measurements and percent fat of 55 lesser prairie-chickens collected from tebuthiuron treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico ...... 79
x LIST OF FIGURES
1.1 Distribution of perpendicular distances (truncated) and fit of the Fourier series estimator for lesser prairie-chickens in tebuthiuron-treated (top) and untreated (bottom) sand shinnery oak rangelands of west Texas and eastern New Mexico, January-February, 1986 ...... 16
1.2 Distribution of perpendicular distances (truncated) and fit of the exponential power series estimator for lesser prairie-chickens in tebuthiuron-treated (top) and untreated (bottom) sand shinnery oak rangelands of west Texas and eastern New Mexico, July-September, 1985 ...... 18
xi CHAPTER I
EFFECTS OF SHINNERY OAK CONTROL ON
LESSER PRAIRIE-CHICKEN DENSITIES
Introduction
The range occupied by the lesser prairie-chicken
(Tympanl1chus :r;>alljdicinctus) has declined over 90% since the
1800' s (Taylor and Guthery 1980h). Lesser prairie-chickens
are currently restricted to scattered portions of Oklahoma,
Kansas, Colorado, New Mexico, and Texas (Cannon and Knopf
1981). Probable causes for their decline include increased
conversion of prairie to cropland (Doerr and Guthery 1983h)
and overgrazing of rangeland (Jackson and DeArment 1963,
Cannon and Knopf 1981) .
Sand shinnery oak (Ollercus havardii) is a shrub capable
of replacing grasses and forming extensive stands with heavy grazing of rangelands. This shrub is able to effectively
compete with grasses because of its extensive root system.
In addition, shinnery oak leaves are toxic to cattle during
spring (Sperry d al. 1964). Primarily because the
increased occurrence of shinnery decreases livestock
stocking rates, it is considered undesirable by many
ranchers (Pettit 1979, Doerr and Guthery 1980). Many
landowners in west Texas and eastern New Mexico have used the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-
1 2 thiadiazol-2-yl]-N,N'-dimethylurea) to control shinnery oak. with the removal of shinnery, grass production can increase
3 to 9 times (Pettit 1979).
Although tebuthiuron is an effective means of controlling shinnery oak, a number of concerns arise in relation to the effects of shinnery oak control on lesser prairie-chickens. Lesser prairie-chickens do occur in areas without shinnery oak (Hoffman 1963, Jones 1963), but the rapid conversion from a shrub-dominated community to a grass-dominated community could impact lesser prairie chicken populations.
Previous work with lesser prairie-chickens indicates that control of shinnery oak may provide improved nesting, loafing, and roosting habitat. Davis d aJ.. (1979) reported that when female lesser prairie-chickens in eastern New
Mexico had access to a variety of plant associations, they preferred to nest in tall grass, and achieved higher nest success in grass-dominated sites. Taylor and Guthery
(1980Q , 1980h) also found that within shinnery oak rangelands, prairie-chickens preferred areas dominated by grass for loafing and roosting during cool seasons.
Conversely, Copelin (1963) suggested that shinnery oak was important to prairie-chickens for shade during summer months. In addition, because forbs and insects may be more abundant in shrub cover (Davis d aJ.. 1979), lesser prairie chickens might be expected to prefer areas dominated by 3
shinnery oak for summer foraging. Where it does occur,
shinnery oak is frequently consumed in all seasons,
especially fall and winter (Davis ~ al. 1979, Doerr and
Guthery 1983~). Because shinnery oak is an important source
of shade and food, removal of this shrub may be detrimental
to lesser prairie-chicken populations (Jackson and DeArment
1963). In addition, tebuthiuron applications are detrimental to sand sagebrush (Artemisia fiJjfoJia) (Doerr and Guthery 1983g ), which can be important for cover, especially when grass production is poor (Jones 1963, Taylor and Guthery 1980h), and as a food source (Jones 1963)
Regardless of how tebuthiuron affects plant communities, the effects on lesser prairie-chicken populations can only be determined by measuring the population response to these treatments. Simply measuring habitat responses does not determine how land-use practices affect lesser prairie-chickens. The effects of tebuthiuron on plant communities has been investigated (Pettit 1979,
Doerr and Guthery 1983g ), but the actual effects of these treatments, and resulting habitat changes, upon lesser prairie-chicken densities have not been studied. The objective of this study was to estimate and compare the density of lesser prairie-chickens in tebuthiuron-treated and untreated sand shinnery oak rangelands. 4
Study Area
Field work was conducted in Cochran and Yoakum Counties
of Texas and Lea and Roosevelt Counties of New Mexico. The
study area is located at the southern portion of the
Southern High Plains or Llano Estacada (Dittemore and Hyde
1960, Turner ~ al. 1974). Mean annual precipitation is 41
em and over 80% of the moisture occurs between May and
October during thunderstorms (Dittemore and Hyde 1960,
Newman 1960, Turner ~ ai. 1974). Range cattle production
is the major land use (Newman 1960) .
The study areas are characterized by the Brownfield
Tivoli fine sand soil association, which produces a gently i undulating and duned landscape. Tall grasses would dominate climax (Pettit 1979). Shinnery oak currently dominates the
area, with less frequent occurrences of sand sagebrush, sand dropseed (Sporobollls cryptandnls), purple threeawn (Aristida
p"rp"rea), and broom snakeweed (Xanthocephalllm sarothrae)
(Dittemore and Hyde 1960, Pettit 1979).
Methods
Weather
Precipitation on the study area was determined by
averaging data from 3 local weather monitors (Natl. Oceanic
Atmosp. Adm. 1985, 1986). Summer temperatures were
estimated by averaging data from 2 local weather monitors
(Natl. Oceanic Atmosp. Adm. 1985). Mean temperatures, and 5
mean high temperatures were determined for each month during
which summer densities of prairie-chickens were estimated.
Stlldy Plots
Plots previously treated with tebuthiuron were compared
with untreated plots. Vegetation on untreated control plots
was dominated by extensive stands of shinnery oak.
Vegetation on treated plots was primarily composed of
several grasses which had replaced shinnery oak.
Tebuthiuron-treated pastures used in this study were
previously treated with the herbicide between 1979 and 1983
at a rate of 0.56 kg/ha (0.5 Ib/acre).
Ve~etatiQn Cornpositjoo
To compare composition of vegetation in treated and
untreated plots, 10 randomly placed 100 point step-point
transects (Evans and Love 1957) were conducted within each
treatment type during 26 September-26 October, 1985 (fall), \, and 5 March-10 April, 1986 (spring). If a point encountered
bare soil, the nearest plant was recorded. The nearest
plant was chosen from the zone in front of an imaginary line
extending 90° from either side of the point. Nomenclature
follows Correll and Johnston (1979). Common names are from
Gould (1969). A Student's t-test (Steel and Torrie 1980)
was used to compare mean basal composition of taxa between
treatment types by season. All tests were made at £<0.05
unless listed otherwise. 6
Density Estimates
Line transect procedures (Burnham ~ al. 1980) were
used to estimate density of lesser prairie-chickens.
However, numbers of lesser prairie-chickens have been
-,;,;. derived in most studies from early morning lek counts (Copelin 1963, Cannon and Knopf 1981). Density estimates
derived from lek counts are biased because females are not
counted and many birds do not attend leks (Taylor and
Guthery 1980h). Furthermore, lek counts allow enumeration
of lesser prairie-chickens only at leks; other habitat types
cannot be sampled with this method.
The primary concept of line transect theory is that not
all birds in an area must be seen to estimate density,
because the probability of an object being seen decreases as
I i its distance from the line increases. Density estimation using line transects requires that 4 assumptions are met: I (1) objects on the line will always be seen, (2) objects do not move prior to detection and are only counted once, (3)
distances and angles are measured exactly, and (4) sightings
are independent events (Burnham ~ al. 1980).
Transects were sampled over 2 time periods: (1) 16
July-16 September, 1985, and (2) 6 January-23 February,
1986. Transects were surveyed only once during each
sampling period. Data were pooled for all untreated and all
treated plots separately to achieve a satisfactory sample
.;~ 7
size of 40 observations for each treatment-period
combination (Burnham ~ al. 1980). During summer, 25 line
transects were sampled in untreated shinnery oak rangeland,
resulting in a total line length of 141.6 km, compared with
47 line transects totalling 204.8 km in treat~d plots.
During winter, 50 transects were sampled for a total length
of 289.4 km in untreated shinnery. In treated plots, 31
line transects were sampled for a total length of 144.2 km.
Transects were traversed by observers counting all
lesser prairie-chickens seen. Transects were surveyed using
a four-wheel drive vehicle. Use of a dashboard compass
located in the vehicle and a hand-held compass facilitated our ability to travel in a straight line. The following
data were recorded for all transects: (1) total length of
lines surveyed, and number of lines surveyed, (2) number of
sightings observed, (3) number of birds in each observed
flock, (4) perpendicular distances from the transect line to the observed sighting point. Perpendicular distances were
recorded using a measuring tape. All transects were located a minimum of 0.8 km from each other and at least 0.2 km from any other treatment type. Transects were marked on aerial photographs and numbered.
Computer program TRANSECT (Laake ~ al. 1979) was used to estimate lesser prairie-chicken density in treated and untreated plots. According to Burnham ~ al. (1980), the 8
number of groups/unit area (Dc) was estimated using the
general formula: Dc nf(O) 2L
where n is the number of observations (groups); frO) is the
probability density function, which indicates the
probability of detecting a group; and L is the combined
length (km) of the line transect. The value frO) was
estimated by fitting an appropriate estimator model to the
perpendicular distance data from each treatment type for
each season transects were surveyed. We examined several
estimators using the goodness-of-fit criteria described by
:I~··. Burnham ~ ai. (1980) to determine which provided the best
fit of the data. We determined the fit to be sufficient if I,· i' the X2 probability value exceeded 0.05. The exponential
I power series estimator was used for summer data, and the t Fourier series estimator for winter data.
Because perpendicular distance data were collected
without a defined width, all data were used for the initial
analysis. When outliers occur, Burnham ~ ai. (1980)
suggest truncating 1-3% of the data. Because the
untruncated data did not provide an acceptable fit (£<0,05),
we truncated 1 observation (2.5%) of the data from each of
the 4 surveys.
Group densities were multiplied by average group size
(C) to estimate density of birds/ha (D), 9
D = DcC nf/OlE 2L
Differences in density estimates between treated and untreated plots were tested using a ~ test (Johnson 1976) on a seasonal basis. Average group sizes were compared using a
Wilcoxon two-sample test by season (Hollander and Wolfe
1973) .
Results
Weather
Total precipitation for 1985 was above the 30-year mean
(Table 1.1). Precipitation during the months in which summer line transects were conducted was above the 30-year average. The above-average precipitation during these 3 months occurred in July and September. Precipitation was below average during winter 1985-86.
Plant Composjtion
Vegetation composition was different between treatments for both seasons (Table 1.2). Shrub composition was greater in untreated pastures during both seasons. Shinnery oak comprised the greatest percentage of plants encountered. In contrast, forbs occurred more frequently in treated pastures than in untreated pastures. However, forbs present changed between seasons. Annual wildbuckwheat (Ed ogonum annuum) composition was greater (£<0.05) in treated plots than in untreated plots during fall. However, compositioh of the -- ~'JYB ~" ':;''':'''~-:~;
Table 1.1. Monthly precipitation (cm) and deviation from the 30-year average (cm) for the study area, 1985-1986.
1985 1986
Deviation Deviation Month Precipitation From Normal Precipitation From Normal
January 1.4 0.5 0.0 -0.9
February 0.8 -0.4 1.9 0.7
March 3.7 2.2 0.3 -1.2
April 1.2 -1. 0 0.4 -1.8
May 7.5 3.0 7 . 9 3.4
June 13.2 7.6 12.8 7.2
July 8.6 2.5 4.7 -1.4
August 2.2 -4.5 7.7 1.0
September 11. 9 6.0 9.3 3.4
October 10.6 6.3 7.4 3.1
November 0.9 -0.4 5.7 4.4
December 0.6 -0.3 5.5 4.6
Total 62.6 21.5 63.6 22.5 ,... 0
.. ".'- Table 1.2. Percent basal composition of vegetation in treated and untreated sand shinnery oak rangelands.
Fall 1985 Spring 1986 ---
Sr.ecies Treated Untreated Treated Untreated
Grasses
Aristida purpurea 2L5 8.6* 30.0 7.1**
Schizachvrium scoparium 17.2 7.9 19.9 17.7
Paspalum setaceum 9.1 3.6* 4.0 0.1*
Sporobolus crvptandrus 9.0 3.7 7.4 2.5
Bouteloua hirsuta 7.0 2.6 8.2 3.6
Munroa squarrosa 3.3 0.0* 0.0 0.0
Other speciesa 11.7 (4 ) 9.1 (5 ) 2.7 (2 ) L8 (2 )
Total 78.8 35.5** 72 .2 32.8**
Grass-like
Total 2.5 4.8 0.2 0.0
Forbs
Eriogonum annuum 4.7 0.4* 0.2 0.1 f-' Heterotheca latifolia 3.9 0.1* 0.0 0.0 f-' .... -"'~,.-~,----.-.-.-~~-.~-...--.,','-..,.,...,...." .,...,...... ~ ~
Table 1.2. Continued.
Fall 1985 Spring 1986
Species Treated Untreated Treated Untreated
Chamaesaracha sp. 0.0 0.0 8.8 0.0**
Lithospermum incisum 0.0 0.0 4.6 0.2*
Other speciesa 8.3 (16 ) 8.5 (13) 10.1 (8 ) 1.6 (7 )
Total 16.9 9.0** 23.7 1.9**
Shrubs
Ouercus havardii 0.7 47.6** 1.6 63.9**
Artemisia fi1ifolia 0.1 1. 8* 1.0 0.9
Other species a 1. 0 (3) 1.3 (2) 1.3 (2) 0.5 (2)
Total 1.8 50.7** 3.9 65.3**
* £<0.05 between treatments within seasons.
** £<0.01 between treatments within seasons. a Species which individually make up less than 5.0% of the total composition in all treatment-season combinations, and do not differ (£>0.05). Number of species is in parentheses. f-' N
---,-- 13
forb was similar between treatments during spring transects. conversely, false-nightshade (Chamaesaracha sp.) was not present in fall, but did occur in tebuthiuron-treated plots in spring. During spring, differences in false-nightshade composition were highly significant (£<0.01) between treatments. Composition of grasses was higher in treated plots than in untreated plots during both seasons (Table
1.2). Among grass species, purple threeawn occurred most frequently. Purple threeawn composition was greater in treated plots than in untreated plots during fall and spring. A complete listing of plants encountered during step-point transects is listed in appendix A.
Density
The density of lesser prairie-chickens was slightly higher in tebuthiuron-treated plots than in untreated shinnery during summer (Table 1.3); however, the difference was not significant (£>0.05). Group sizes were similar
(£>0.05) between the 2 treatment types. Average group sizes in treated plots were 3.38 and mean group sizes in untreated plots were 3.42. Broods accounted for (10%) and (15%) of the groups detected in untreated and treated plots, respectively.
During winter, density was 53.8% higher in treated plots than in untreated plots. Nevertheless, this difference was not significant (£>0.05). However, Dc values """""":iif :." -.~",.
Table 1. 3. Density of lesser prairie-chickens in tebuthiuron-treated and untreated sand shinnery oak rangelands during summer (July-September) 1985 and winter (January- February) 1986.
f(O)c Dcd ce Df
Survey N wa Lb (m) (kIn) x SE x SE x SE x SE
Surruner
Treated 39 53.0 204.8 0.159 2.048 0.152 1. 950 3.38 0.521 0.51 1. 06
Untreated 39 67.7 141. 6 0.087 0.719 0.120 0.991 3.42 0.572 0.41 0.55
Winter
Treated 39 47.8 144.2 0.064 0.011 0.086 0.020 6.18 1.033 0.53 0.09
Untreated 39 95.4 289.4 0.048 0.008 0.032 0.008 10.68 2.080 0.35 0.07 a Transect width after truncation. b Total line length.
C Inversely proportional to the probability of detecting a group. d Groups/ha. e Average group size.
f Birds/ha.
t-' "'" 15
were higher (£<0"01) in tebuthiuron-treated plots than in
untreated plots. The discrepancy is due to differences in
group sizes between treatment types. Mean group size in
treated plots was 6.18, compared with 10.68 birds in
untreated plots. However, winter group sizes were not
different between treatments (£>0.05).
Distributions of perpendicular distances from the I I , I transect line to the detection point varied between !; I , I treatments. Histograms revealed that the distribution of I( perpendicular distances occurred closer to the transect line !,
in tebuthiuron-treated plots than in untreated plots. This
was particularly noticeable during winter. During winter,
70% of the groups in tebuthiuron-treated plots were S 15 m
of the line; and 2.5% of the groups were ~ 48 m (Figure
1.1). By contrast, 52.5% of prairie-chicken groups recorded
in untreated shinnery were S 15 m from the line; and 22.5%
of perpendicular distances were ~ 48 m from the line (Figure
1.1) . In addition, 25% of prairie-chicken groups detected
in treated pastures were within 0.2 km of untreated
shinnery, and 17.5% of observed groups in untreated pastures
were within 0.8 km of harvested grain fields. Twenty
percent of the groups found in untreated plots contained at
least 15 birdS, and 15% of the groups contained at least 20 birds. Conversely, only 7.5% of groups in treated plots
contained 15 Or more birds and 5% contained 20 or more
i- 1
, \, ! 16 0.0701
0.0623 WINTER TREATED >-< 0.0545 E-< H rJl 0.0467 :z r::l"" 0.0390 >-< E-< H 0.0312 H H 01 ,0: 0.0234 01 0 0:: 0.0156 p.. 0.0078 3 3 2 <0.0001
0.0 8.0 16.0 23.9 3l. 9 39.9 47.9
0.0528 0.0470 WINTER UNTREATED 0.0411 18 0.0352 0.0294 0.0235 0.0176 0.0117 0.0059 2 2 <0.0001 1 1 1
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 PERPENDICULAR DISTANCE (M)
Figure 1.1. Distribution of perpendicular distances (truncated) and fit of the Fourier series estimator for lesser prairie-chickens in tebuthiuron-treated (top) and untreated (bottom) sand shinnery oak rangelands of west Texas and eastern New Mexico, January-February, 1986. Values w::.thin histogram bars represent the number of groups observed in each distance interval. 17 birds. In addition, all observed groups containing at least
20 birds occurred in or within 0.2 km of untreated shinnery.
During summer, perpendicular distance distributions also differed between treatments, although not to the same extent as in winter. During summer, 52.5% of the groups recorded in treated plots were ~ 5 m from the line (Figure
1. 2) . In contrast, only 35% of the groups were ~ 5 m from the line in untreated shinnery (Figure 1.2). In addition,
22.5% of all groups detected in treated pastures were within
0.2 km of untreated shinnery.
DjsCl1ssiop
Doerr and Guthery (1983a) noted that tebuthiuron applied to shinnery oak rangelands at rates of 0.4-0.6 kg/ha, caused forb densities to decline, but only for 1 year. Similarly, step-point transects conducted in 1985 and
1986 indicated that percent composition of forbs was greater
in plots previously treated with 0.56 kg/ha of tebuthiuron than in untreated plots. These data suggest that forbs i' ,. recover rapidly after tebuthiuron applications.
Precipitation during the first 4 months of 1985 was above the 30-year mean and occurred early enough to benefit forbs.
In drier years, forb composition may be lower than we detected in 1985. Precipitation during winter of 1985-86 was below the 30-year mean. As a result, forb production in spring 1986 may have been lower than normal. 18
0.1753
0.1558 >-< 0-< H 0.1363 SUMMER TREATED {fJ Z w 0.1168 0 >-< 0.0974 0-< H H 0.0779 H (Q .t: 0.0584 (Q 32 0 ~ p., 0.0390
0.0195 2 <0.0001 5 0.0 13 .3 26.5 39.8 53.0
0.0957
0.0850 >-< 0-< H 0.0744 SUMMER UNTREATED {fJ Z W 0.0638 0 >-< 0.0532 0-< H H 0.0425 H (Q .t: 0.0319 (Q 0 ~ 0.0213 p., 0.0106 4 1 0.0 0.0 16.9 33.8 50.7 67.7
PERPENDICULAR DISTANCE (M)
Figure 1.2. Distribution of perpendicular distances (truncated) and fit of the exponential power series estimator for lesser prairie-chickens in tebuthiuron treated (top) and untreated (bottom) sand shinnery oak rangelands of west Texas and eastern New Mexico, July September, 1985. Values within histogram bars represent the number of groups observed in each distance interval. 19
Lesser prairie-chicken densities were higher in treated plots than in untreated plots during both winter and summer, although these differences were not significant. This is consistent with Davis ~ £1. (1979), who noted that concealing plant cover may be better in areas with more tall grass and fewer shrubs, especially during winter.
Differences between treatments in the distribution of perpendicular distances indicated that lesser prairie- chickens were more difficult to detect in treated plots than in untreated plots. This suggests that cover in tebuthiuron-treated pastures may be superior to that in untreated shinnery. This is particularly true during winter, after oak leaves have dropped. While shinnery substrates are bare in winter, tall grasses continue to provide cover for birds, and may be preferred areas for loafing and roosting during cool seasons (Taylor and Guthery
1980a, 198Gb,)
Copelin (1963) stated that lesser prairie-chickens required shinnery oak areas for shade during summer. He also noted that this requirement was critical during times of drought or when temperatures neared or reached 37.8° C.
Average temperatures during the 3 months of summer transects
(July-September, 1985) were within 1° C of the 3D-year average. The average maximum temperatures were 33.6° C,
34.5° C, and 29.0° C for July, August, and September, respectively. In addition, daily high temperatures reached 20 or exceeded 35° C a total of 21 days (33%) during the period of summer line transects. Thirteen of these 21 days occurred in August. Precipitation was also slightly above the 30-year mean for the time when line transects were surveyed. During a warmer and/or drier summer, shade provided by shinnery oak may be more critical to prairie chickens, and may cause densities in untreated shinnery to be greater than detected.
The large flocks observed in or near untreated shinnery or harvested fields in winter may have been congregating at specific sites to feed on acorns or waste grain. Taylor
(1978) and Copelin (1963) observed large flocks of over 80 lesser prairie-chickens feeding in harvested sunflower and grain fields during winter months. Campbell (1972) also suggested that the location of grain fields may have influenced prairie-chicken movements. In addition, shinnery oak acorns are an important fall and winter food for lesser prairie-chickens (Jackson and DeArment 1963, Crawford and
Bolen 1976, Davis ~ al. 1979). Large feeding flocks would be more advantageous than small groups or individuals in detection of predators (Pettingill 1970). This situation would be especially advantageous when prairie-chickens are forced to forage in areas where concealing cover is limited.
Davis ~ al. (1979) found that as winter progressed and the need for acorns increased, selection for concealment decreased, and prairie-chickens foraged in areas where shrub 21
and grass compositions were similar to the overall habitat.
Similarly, we found that within untreated shinnery oak, 55% of all groups detected during winter were located in areas where composition of tall grasses or sand sagebrush was greater than what was generally available.
Management ImplicatJons 1-, .: Tebuthiuron applications on shinnery oak rangelands rI result in increases in grass composition as shrub composition decreases. Forb composition appears to increase within a few years after chemical treatment. The changes in vegetation composition appear to have little effect on
lesser prairie-chicken densities, especially during summer.
Increased production of tall grasses in treated pastures may \' provide superior concealing cover to that found in untreated shinnery. However, in shinnery oak rangelands, lesser j;" !~. ;- .'; 'i, I; prairie-chickens may require shinnery oak, whether as a food source or for shade during summer months. Even within tebuthiuron-treated plots with abundant tall grass cover, prairie-chickens were often found near untreated shinnery oak. Lesser prairie-chickens may benefit by preservation of scattered sites of untreated shinnery. A mosaic of the two treatment types would produce the most desirable situation, by making areas of both untreated shinnery and tall grasses available to lesser prairie-chickens. CHAPTER II
EFFECTS OF SHINNERY OAK CONTROL ON LESSER
PRAIRIE-CHICKEN DIET AND GUT MORPHOLOGY
Tnt roduct ion
Lesser prairie-chickens (Tym);lanllchus );lallidicinctus) " i are presently restricted to scattered portions of Colorado,
Kansas, Oklahoma, New Mexico, and Texas (Taylor and Guthery
1980Q , Cannon and Knopf 1981). The occupied range of this bird has decreased over 90% since the 1800's (Taylor and
Guthery 19800.) .
Sand shinnery oak (Ouercns havardii) is a shrub capable of replacing grasses and forming extensive stands after heavy grazing (Pettit 1979). This shrub has an extensive root system, allowing effective competition with grasses.
In addition, shinnery oak leaves are poisonous to cattle during spring (Sperry ~ al. 1964). Because the increased incidence of shinnery oak decreases stocking capacity, it is considered undesirable by many ranchers (Pettit 1979, Doerr and Guthery 1980). In west Texas and eastern New Mexico, tebuthiuron (N-[5-(1,1-dimethylethy1)-1,3,4-thiadiazol-2- yl)-N,N'-dimethy1urea) has been used to effectively control shinnery oak and allow grass production to increase 3-9 times (Pettit 1979).
22 23
The removal of shinnery oak from rangelands raises a
number of questions concerning the effect of shinnery
control on lesser prairie-chickens. While ingestion of
tebuthiuron presently shows no health hazards in study
animals, (Emmerich 1985) the rapid conversion of a shrub
dominated community to a grass-dominated community could
have significant impacts on lesser prairie-chicken
populations.
The quality and quantity of food consumed by upland
game birds often dictates the condition of a bird. If
nutritional requirements are not met by available foods, , ~
condition may decline, resulting in decreased survival and
reproductive potential. In habitats where suitable food is
plentiful, birds can choose diets that will support good
growth and reproduction (Scott 1973).
Davis ~ ai. (1979) and Jones (1963) found that insects
were a major summer food for lesser prairie-chickens. Green
plant material, including both forbs and shinnery oak
leaves, was also an important food (Davis ~ ai. 1979)
Insects and forbs may be affected by tebuthiuron. Pettit
(1979) reported that tebuthiuron adversely affected forb production and this could cause decreased insect availability. Doerr and Guthery (1983a) found that with low application rates of tebuthiuron, seed and forb production .' increased, but insects may have decreased. However, the actual effects of these treatments, and resulting habitat 24 changes, upon lesser prairie-chicken diets have not been studied. Our objective was to evaluate and compare the diets and gut morphology of lesser prairie-chickens collected in tebuthiuron-treated and untreated shinnery oak rangeland.
Study Area
Field work was conducted in Cochran and Yoakum Counties of Texas and Lea County, New Mexico. The study area is located in the southern portion of the Southern High Plains
(Dittemore and Hyde 1960). Mean annual precipitation is 41 cm and over 80% occurs between May and October (Dittemore and Hyde 1960, Newman 1960, Turner ~ al. 1974) Range cattle production is the primary land use (Newman 1960) .
The study areas are characterized by the Brownfield
Tivoli fine sand soil association, which produces a gently undulating and duned landscape. Tall grasses historically dominated the area, but have been replaced by thick stands of shinnery oak, with less frequent occurrences of sand sagebrush (Artemisja fi1ifoJia), sand dropseed (SporohoJl1s cryptandrus), purple threeawn (Aristida p"rpurea), and broom snakeweed (Xanthocephalum sarothrae) (Dittemore and Hyde
1960, Pettit 1979).
Methods
Precipitation on the study area was determined by averaging data from 3 local weather monitors (Natl. Oceanic 25
Atmosp. Adm. 1984, 1985). Precipitation was divided into pre-collection (January-April), and collection (May-July) periods.
Male and female lesser prairie-chickens were collected by shooting between 27 May and 3 July during 1984 and 1985 on tebuthiuron-treated and untreated sand shinnery oak rangelands. Vegetation in untreated control plots was dominated by extensive stands of shinnery oak. Vegetation on treated plots was primarily composed of grasses which had replaced shinnery oak (see chapter 1). Tebuthiuron-treated pastures used in this research had been treated with the herbicide at a rate of 0.56 kg/ha between 1979 and 1983.
Crops were removed and frozen immediately after collection. Birds were also frozen for laboratory analysis.
In the laboratory, gizzards were emptied and weighed to the nearest 0.01 g. Small intestines and caeca were removed and measured to the nearest 0.1 cm. Care was taken to insure that the structures were straightened, but not stretched
(Moss 1983). Both caeca were measured separately and were added together to obtain a total combined length. Guts were rinsed free of all ingesta and feces, blotted dry and weighed to the nearest 0.01 g.
Crops were emptied of all contents, which were rinsed to remove blood and grit. Foods were sorted and identified using a binocular dissecting microscope (7-30x). Borror ~ ai. (1981) was used to identify and classify insects. 26
Correll and Johnston (1979) was used to identify plants
found in crops, and common names are from Gould (1969)
Food items were counted and volumes were measured by
volumetric displacement in a graduated cylinder (Swanson and
Bartonek 1970). Volumes were recorded to the nearest 0.01
mi. When volumes were too small to be measured, they were
assigned a value of 0.005 mi. Items were also dried for ~
48 hours at 60° C and weighed to the nearest 0.0001 g. Only
volumes were recorded for birds collected in 1984.
Diet composition was based upon aggregate percent
volume and aggregate percent weight. Volumetric
measurements of each item are expressed as the mean of all
volumetric percentages for that item (Swanson ~ al. 1974,
Prevett ~ al. 1979).
Diets were analyzed using a Kruskal-Wallis K-sample
test by year of collection with treatment type as the
independent variable. Data were lumped for both sexes.
Items with less than a 15% occurrence in all treatment-year
combinations were combined with similar items for analysis.
Prairie-chicken gut morphology was analyzed using a 2x2
factorial analysis of variance with treatment type and
collection year as independent factors. Data were lumped
for both sexes. Because data were not balanced, least
square means, rather than observed means, were analyzed.
Data were tested for normality using a Shapiro-Wilk W test.
A Bartlett's test was used to test for homogeneity of 27 variances (Steel and Torrie 1980). When treatment variances were heterogeneous (as indicated by a significant Bartlett's test), treatments were compared following the approach of
Milliken and Johnson (1984), who recommended using a weighted combination of heterogeneous error terms. · " Interactions were analyzed using a Fisher's Protected Least ! ;
': . Significant Difference (FLSD) test on the means. All tests were made at ~<0.05.
Results
Precipi tat j ou
Total precipitation during 1984 was 34.8% above the 30- year average (Table 2.1). In 1985, total precipitation was
52.3% above the 30-year average and was 13.0% (7.2 cm) greater than in 1984. A major portion of this difference between the two years occurred from January through April.
· "
During these 4 months, 1985 precipitation exceeded 1984 · " precipitation by 6.3 cm (787.5%). Precipitation for these 4 months was less than the 30-year average by 5.0 cm (86.8%) in 1984, and exceeded the 30-year average by 1.3 cm (22.4%) in 1985. During the 3 months in which prairie-chickens were collected, 1985 precipitation exceeded 1984 precipitation by
4.7 cm (19.1%). Precipitation for these 3 months exceeded the 30-year average by 8.4 cm (51.8%) in 1984 and by 13.1 cm
(80.9%) in 1985. Table 2.1. Monthly precipitation (cm) and deviation from the 30-year average (cm and percent) for the study area. Data are broken down by pre-collection (January-April) and collection (May-July) periods.
Year Period Precipitation Deviation from Normal
1984 Total 55.4 cm 14.3 ( 34.8%)
Pre-collection 0.8 cm -5.0 (-86.2%) Collection 24.6 cm 8.4 ( 51. 8%)
1985 Total 62.6 cm 21. 5 52.3%)
Pre-collection 7.1 cm 1.3 22.4%) Collection 29.3 cm 13.1 80.9%)
IV ro
- ;:~:-.."·.", ... ,'£s:::,,,_c;'B.s''',~iE''"'~'ii~c''c.i,~~;i~~~~~~~~=~= ;;=..... uIlWM-!\,&:l!!liIIZ·i£EJIllil!'l.,,,£.'l:-lIli4ll1w::HR4;p·WPk = 29
Volumes of food items were different for lesser
prairie-chickens in tebuthiuron-treated pastures and
untreated shinnery oak pastures. During 1984, total plant
matter was greater (E plots than in untreated plots (Table 2.2). Similarly, total leaf and flower consumption was also greater in birds from treated plots (E 1985, no difference existed between treatments for total plant or total leaf and flower matter (E>O.05). Nevertheless, prairie-chickens still consumed 84.5% more leaves and flowers in treated plots than in untreated plots. Consumption of shinnery oak acorns was greater (E 1985. Birds in untreated plots also ate more shinnery oak foliage than birds in treated plots (Table 2.2) . During 1984, fleabane (Erigeron spp.) foliage represented a greater proportion of the diet in treated plots than in untreated plots (Table 2.2). Within treated plots, fleabane foliage was the most important food item...... --.. ~~'---."".---~------, -- ~ ',"'''''i,:~ ""-- .,," .. ~ .. ~ .. "... ",,,: .., ... " .. =,., '''''''''----:::'.'''=10 .. , ..n.,,,·,,...!'?,,,,,. ,,'" fC,.'!. .•'A ...... ::""" """" .,".:., '.. "N', .,d,.F... ,....,. :i:''''"ZW Table 2.2. Food items from lesser prairie-chickens (N=42) collected during summer (27 May-3 July) in tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico. 1984 1985 Treated Untreated Treated Untreated (N=6) (N=9) (N=15) (N=12) Food Items % Volume % Volume % Volume % Dry Wt. % Volume % Dry Wt. Foliage and Flowers Er.iqerQ!l spp. 60.59 10.09* Trb Tr 0.00 0.00 Thelesperma sp. 17.91 5.61 4.88 3.53 2.19 1. 48 Senecio riddelLii 0.00 0.00 8.24 7.44 0.00 0.00 C;yclQlo!llg 6.88 0.00 2.84 2.25 0.00 0.00 gtriplicifQlium Cr:Y>ltgIltba 0.00 0.00 6.80 6.36 1.18 0.68 jamesii Quercus havardii 0.00 0.00 0.62 0.64 6.54* 3.39* 12etalQsteIDuID 0.00 0.00 4.97 6.42 0.33 0.16 >lurpur:eum Commelina erecta 0.00 0.00 0.13 0.09 8.86 8.40 w 0 -" ';-;.,: ~-'''''.';,:': :;T:"-"---' Table 2.2. Continued. 1984 1985 Treated Untreated Treated Untreated (N=6) (N=9) (N=15) (N=12) Food Items % Volume % Volume % Volume % Dry Wt. % Volume % Dry Wt. Eriogonum annuum 7.23 0.00 5.69 6.09 0.00 0.00 Other grassesa 0.00 0.76 0.56 0.24 3.25 0.28 Other forbsa 6.00 5.01 11.31 9.79 2.60 1. 32 Total foliage and flowers 98.61 21.47** 46.03 42.87 24.95 15.70 Fruitsa 0.00 0.00 0.74 0.77 7.13 8.68 Seeds Linum rigidum 0.00 0.00 11.20 8.97 0.02 0.04 Other seedsa 0.00 0.00 7.05 5.79 0.22 0.16 Total seeds 0.00 0.00 18.24 14.76 0.23 0.20 Acorns Ouercus havarrtii 0.00 59.86** 0.00 0.00 35.83** 46.77** 0.00 0.84 0.78 0.11 0.03 w Unknown plants 0.00 f-' Ii .£ _ "'."..c,_'"'' '..ce._ -'-i~"'?·~-_,,":.,.'i,'~" .. '_"~"" __-C "'-""Si'='=-"'-'''' ,~·' .. ..£.. '~~::-2~".,.." .•:.~·;~,i: ~.c~':<:: .,::',c,,,.,,",,=_.,_,.,_, ".. ,c,.~" "" .... ,',' .... , .. 'c'oc' -, ,--,.~~ -~'~~"'~l-":"'""""_"'""""-:_'~""""'"t".,.,.."~,,,, .' . '-.:";::~'7' ., ",~.:. '.iA-." _~'<~L'" .'''£1"4,0'' ,:,< ,9i.~, "P',,:,,:,;'. :,:1;~- "" '·~"""1; ,,'\'" ,Ji¥ .' "f:,~;o;h,y," Ii% '";r~r',!5ibSL ,1l!~.'ffli:&l\ilf&N Table 2.2. Continued. 1984 1985 Treated Untreated Treated Untreated (N=6) (N=9) (N=15) (N=12) Food Items % Volume % Volume % Volume % Dry Wt. % Volume % Dry Wt. Total plant 98.62 81.33** 65.85 59.19 68.26 71.37 Animal Foods Membracidae 0.00 17.12** 1. 84 3.76 14.67** 14.01** Acrididae 0.78 1.35 16.36 15.96 15.15 13.42 Pentatomidae 0.00 0.00 3.68 5.20 0.44* 0.44* Chrysomelidae 0.00 0.00 3.18 5.97 0.00* 0.00* Other Insects 0.61 0.20 9.08 9.92 1. 49 0.75 Total Animal 1. 38 18.67* 34.15 40.81 31. 74 28.62 a Foods that individually accounted for < 5% of the diet (% volume or % dry weight) in all treatment-period combinations, and did not differ (£>0.05). b Tr <0.01% of the diet. * £<0.05 between treatments within years. W ** £<0.01 between treatments within years. N ,I, .' '. .. ,. . .. .~",..:,.. , .. ",,"~,,,:",, ·"i,,' ,~". cc,,'" "="""" ·",~i~·"',,··=,,·.;·="-':.~. """. '=o ••"c ="''''''~''~i:'''~''';''''' ~';"" ... ' "", .. "".-"',. "...... ~, .·'··c","" '• 33 This plant accounted for 61.4% of all plants eaten in 1984 by birds in treated pastures. Only trace amounts «0.01%) of fleabane were consumed in 1985. In both years, tumble ringwing (Cycloloma atriplicifolium) and annual wildbuckwheat (Eri ogonum annuum) foliage occurred only in diets of birds from treated plots (Table 2.2). James cryptantha (Cryptantha jamesii) foliage also occurred more often in the diets of prairie-chickens from treated pastures. During 1984 no grass or forb seeds were eaten in either treatment type (Table 2.2). However, in 1985 grass and forb seeds were consumed by prairie-chickens in both treatment types. Although no differences existed between treatments (£>0.05), seed consumption in treated pastures was much greater than in untreated pastures. Stiffstem flax (Linum rigidum) seeds were consumed more than any other seed in treated plots (Table 2.2). Similarly, consumption of fruits did not occur in either treatment type during 1984 (Table 2.2). In 1985, fruits were consumed by prairie-chickens in both treatment types. During 1984, total animal matter consumed was greater in untreated plots than in treated plots (£.<0.05). Birds in untreated plots ate greater amounts of treehoppers (Membracidae) than birds in treated plots (Table 2.2) There was no difference (£.>0.05) between treatments for ,-\ ) , 34 total animal matter consumed in 1985. However, treehoppers were still consumed in greater amounts by prairie-chickens in untreated plots than by those in treated plots (£<0.01) -Stink bugs (Pentatomidae) were consumed in greater amounts in treated plots than in untreated plots during 1985 (Table 2.2). Similarly, prairie-chickens ate more leaf beetles (Chrysomelidae) in treated plots than in untreated plots in 1985 (£<0.05). Both stink bugs and leaf beetles were exclusive to diets of birds collected during 1985. Prairie-chicken consumption of short-horned -grasshoppers (Acrididae) was similar between treatments for both years (Table 2.2). However, grasshoppers represented a larger portion of the diet in 1985 than in 1984. Aggregate percent dry weight values for 1985 followed the same trends displayed by aggregate percent volume (Table 2.2). Total leaf and flower matter consumed in treated plots was much greater than in untreated sites, although this difference was still not significant (£>0.05). As with volume, aggregate percent dry weight revealed treatment differences in acorn consumption. Gut Morphologv Caeca length of lesser prairie-chickens in treated pastures was 11.4% greater than caeca length of birds in untreated plots (Table 2.3). Caeca weights were 25.7% greater in 1984 than in 1985 (Table 2.4). Although there .r c,'-'·' ';'·;·'T-··~'"'·';';;·'·'··'-·".·,;:.'::r·'·""',m" '"";~"-'---":e:!'7"""75r"'''''''''~!'':,s:" "',""",W~"I~~ Table 2.3. F-va1ues from 2-way analysis of variance (ANOVA) of lengths and weights of digestive tract parts of lesser prairie-chickens collected May-July, 1984-85 from tebuthiuron-treated and untreated sand shinnery oak rangelands. Source of Intestine Intestine Caeca Caeca Gizzard variation df length weight length __weight_ weight Treatment 1 5.77* L 69 6.63* 2.18 12.17** Year 1 0.66 0.06 0.41 10.87** 28.15** Treatment x Year 1 3.77 0.65 0.05 0.17 0.31 Errora 49b 229.00 1. 70 162.20 0,80 5.40 a Mean squared errors. b Error degrees of freedom for intestine length=31; for caeca 1ength=17; for gizzard weight=50. * £<0.05. ** £<0.01. w Ul ~", '"_ ....."., .. -~,; ~...... ''''-'' Table 2.4. Average weights (g) and lengths (cm) of the digestive tracts of lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands. Values are expressed as least square means ± SE. Caeca Small Intestine Gizzard (N=53) (N=53 ) (N=54) Length:VVeight Length Wei,gllt_ Weight Treated 1984 99.0 ± 4.50 4.5 ± 0.32 115.4 ± 5.35 4.5 ± 0.46 11. 3 ± 0.77 1985 95.6 ± 2.85 3.8 ± 0.21 119.7 ± 3.38 4.7 ± 0.30 15.2 ± 0.52 x 97.3a ± 2.66 4.1 ± 0.19 117. Sa ± 3.16 4.6 ± 0.27 13.2c± 0.47 Untreated 1984 88.1 ± 4.03 4.2 ± 0.29 113.6 ± 4.78 4.3 ± 0.41 l3.9 ± 0.74 1985 86.5 ± 3.29 . 3.2 ± 0.24 103.0 ± 3.91 3.9 ± 0.34 17.1 ± 0.60 x 87.3a ± 2.60 3.7 ± 0.19 108.3a ± 3.09 4.1 ± 0.27 15.5c ± 0.47 Combined 1984 x 93.5 ± 3.02 4.4b ± 0.22 114.4 ± 3.59 4.4 ± 0.31 12.6b ± 0.53 1985 x 91. 1 ± 2.18 3.5 ± 0.16 111.4 ± 2.58 4.3 ± 0.22 16.1 ± 0.40 a £<0.05 between treatments. b £<0.01 between years. c £<0.01 between treatments. w 0) 37 were no treatment di.fferences, caeca weights exhibited the same trends as caeca lengths. Small intestines were longer in birds from tebuthiuron- treated plots than in birds from untreated plots (Table 2.3). Although there was not a treatment*year interaction (£.>0.05), treated plot birds had 16.2% longer intestines than untreated plot birds in 1985, while intestines of treated plot birds in 1984 were only 1.6% longer than in untreated plot birds (Table 2.4). Intestine weights exhibited no diffeI'ences between years or treatments, but displayed trends similar to intestine lengths. Gizzards were 17.4% heavier in birds collected from untreated shinnery than in birds from treated plots (Table 2.4). Prairie-chicken gizzards were also heavier in 1985 ! " than in 1984. Discussion Plant material made up the bulk of the summer prairie- chicken diet in both years of the study. During 1984, total plant material consumed was greater in birds from treated plots than in birds from untreated shinnery. This occurred even though acorns represented 59.9% of the diet in untreated sites, while not occurring at all in treated sites. Foliage and flowers represented 100% of the plant material eaten by prairie-chickens in treated pastures during 1984. The vegetation component of the prairie- 38 chicken diet was different between treatments in 1984. Conversely, during 1985, total plant material eaten was not different between treatments. Nevertheless, foliage and flowers consumed were still 84.5% greater in the treated Ii diet than in the untreated diet. Shinnery oak acorns were a :H i' major food item during both years in untreated diets, but , were absent in treated diets. Although shinnery oak acorns are reported to be of greatest importance during fall and winter (Crawford and Bolen 1976, Davis ~ al. 1979, Doerr and Guthery 1983h), they are consumed throughout the year. While Doerr and Guthery (1983h) reported no consumption of acorns during summer, Davis d al. (1979) found that acorns accounted for 21.2% of the summer diet of adult prairie-chickens. Davis ~ aI. (1979) reported that vegetative material (leaves and flowers) made up 23% of the prairie-chicken summer diet. This is similar to our data for prairie- chickens in untreated plots during 1984 and 1985. In contrast, Doerr and Guthery (1983h) noted that 40% of the summer diet was foliage, which may have been due to their analysis (fecal analyses are subject to differential digestion). Both studies reported that erect dayflower (Commelina erecta) foliage was a major contributor to the vegetation component of the diet. We found consumption of erect dayflower foliage and flowers similar to these studies only among birds collected in untreated plots during 1985 39 (Table 2.2). In addition, Doerr and Guthery (1983h) found that James cryptantha represented the bulk of foliage eaten in summer, and was a preferred food. Conversely, we found this forb present in the diet only in 1985, and in smaller amounts than previously reported. The importance of James cryptantha may have been overestimated by the fecal analysis used by Doerr and Guthery (1983h). Doerr and Guthery (1983a) suggested that an increase in I the number of seeds, such as stiffstem flax, and other foods 1 I resulting from tebuthiuron treatments might be able to j' I ,I offset the loss of shinnery oak acorns. This does not "\ appear to be the case during summer. While stiffstem flax and other seeds were eaten in greater amounts in treated plots during 1985, total consumption of seeds and fruits in treated plots failed to compensate for the loss of shinnery oak acorns and foliage (Table 2.2). Most of this difference was made up by foliage and flowers from various forbs. Davis ~ Ql. (1979) also reported that seeds represented a minor portion of the summer diet. Lesser prairie-chickens consumed a greater variety of forbs in treated plots than in untreated plots during both years. Doerr and Guthery (1983~) stated that tebuthiuron applications of 0.4 and 0.6 kg/ha did not decrease forb populations and may have increased forb diversity, therefore providing a greater variety of prairie-chicken foods. Doerr and Guthery (1980) indicated that a high diversity of forbs = 40 was a reasonable goal of habitat management for lesser prairie-chickens. An increased diversity of forbs would not only provide a greater variety of vegetative material, but also a greater number of insects which are associated with forbs (Jones 1963) . The number of food items eaten during 1985 was more diverse within both treatments than in 1984, possibly because of the larger sample size in 1985. Also, increased ! ' I diversity in 1985 may be due to an increased availability of ! ; certain items, therefore providing an increased selection of foods; or to decreased availability of certain prominent 1984 foods, such as fleabane and greenthread (Thelesperma sp.) foliage (Table 2.2). Such a response by both plants and insects might be due to the different precipitation in 1984 and 1985, as precipitation in 1984 became available largely after the initiation of the growing season (Table 2.1) In previous investigations of lesser prairie-chicken summer diets, animal matter has been a primary component of the diet. Jones (1964) found that insects comprised 37.9%, 51.3%, and 41.1% of the total diet for May, June, and July, respectively. Davis.at. al. (1979) reported that 55% of the summer diet of adult-sized birds was animal matter. Similarly, Doerr and Guthery (1983h) noted that 59.6% of the summer diet was composed of insects. All three studies indicated that grasshoppers (Orthoptera) represented the 41 bulk of the animal matter eaten. Doerr and Guthery also reported that prairie-chickens preferred grasshoppers to other insects and preferred hoppers (Homoptera) to insects other- than grasshoppers. In contrast, insects made up no more that 19% of the summer diet in 1984, and no more than 35% of the diet in 1985. In addition, short-horned grasshoppers were minor items in the 1984 diet and represented less than 50% of the insects eaten in 1985. The remainder of the animal component of the diet was made up primarily of treehoppers, stink bugs, and beetles. In both years, more treehoppers were consumed in untreated than treated pastures. Prairie-chickens in ! " treated plots may have eaten more stink bugs and leaf beetles to compensate for the loss of treehoppers. Conversely, stink bugs and leaf beetles may have been more common in treated plots, and birds were selecting for these specific insects. However, Davis ~ al. (1979) reported minimal consumption of these insects and Doerr and Guthery (1983Q) reported that beetles (Coleoptera) were not preferred as much as grasshoppers or hoppers. In years when . I other insect groups are rare, treehoppers may represent the majority of insects and may occur primarily in untreated shinnery, since treehoppers are often associated with shrubby vegetation (Lutz 1921, Lawson 1922) . Several insect groups, particularly grasshoppers, are known for annual population fluctuations, often as a result 42 of various weather conditions (Uvarov 1931). Therefore, it is possible that grasshoppers were relatively unavailable to t prairie-chickens during the summer of 1984. Davis ~ al. ,I r r~ (1979) found that while adult prairie-chickens ate more F r grasshoppers than any other insect, treehoppers were also an important food item. This was especially true in early summer, as in this study, before grasshoppers became abundant. Lesser prairie-chickens may depend upon treehoppers during the summer more than previously suggested. Leopold (1953) stated that species living primarily on leafy materials with high fiber content have relatively larger digestive systems than do those eating seeds and fruits with low fiber content; this relationship also exists intraspecifically when birds in different sites eat different foods. Moss (1972) found intraspecific differences in length of digestive systems between birds eating different foods. In this study, intestines were longer in birds from treated sites than in birds from untreated plots. Caeca lengths were also greater in treated pastures than in untreated pastures. The differences in gut lengths and weights between treatment types support the data for dietary differences between treatment types. During both years, prairie- chickens ate more plant foliage in treated plots than in untreated plots. Likewise, prairie-chickens collected from 46 43 treated plots had larger gut lengths and weights than birds from untreated plots. The increased gut sizes may have developed along with an increasing need for cellulose digestion, because of the increase in foliage consumption. Moss (1974, 1983) indicated that gizzard weights were largely determined by diet. He found larger gizzards in spruce grouse (Dendragapus canadensis) and ptarmigan (Lagopus spp.) which ate foods that were difficult to grind. Gizzards weighed more in prairie-chickens from untreated plots than in prairie-chickens from treated plots (£<0.01) These differences in gizzard weight would support the differences found in diets of birds collected from different treatment types. In both years, prairie-chickens ate a substantial amount of shinnery acorns in untreated plots, but none in treated plots. Acorns are a hard food that generally require rigorous maceration by the gizzard before reaching a digestible state. Gizzards were heavier in 1985 than in 1984. Consumption of seeds and fruits may be responsible for heavier gizzards in 1985, even though acorn consumption declined. Conclusions Tebuthiuron applications on shinnery oak rangelands produce a variety of effects which affect lesser prairie chicken food habits. Summer diets are different between birds in treated and untreated shinnery oak plots. Such 44 diet changes correspond to changes in gut morphology. Lesser prairie-chickens consumed a more fibrous, lower quality diet in treated plots than in untreated shinnery during the summer months. The increased consumption of foliage and seeds of forbs in treated pastures may be an attempt to compensate for the loss of shinnery oak acorns. Similarly, the greater consumption of leaf beetles and stink bugs in treated plots may have been to compensate for the loss of treehoppers, because consumption of grasshoppers was not different between treatments. The increase in forb diversity that Doerr and Guthery (1983a) found in tebuthiuron-treated plots may be beneficial during years of poor acorn availability. However, when acorns are available, prairie-chickens appear to find a higher quality diet in untreated shinnery. As a result, an interspersion of the two treatment types on native rangeland might be a viable management option for lesser prairie-chickens. He CHAPTER III NUTRIENT RESERVES OF LESSER PRAIRIE- CHICKENS IN TREATED AND UNTREATED SHINNERY OAK RANGELAND Introduction The range occupied by the lesser prairie-chicken (Tym~anllchus palljdicinctus) has declined over 90% since the 1800's (Taylor and Guthery 1980h). Current range of lesser prairie-chickens in west Texas and eastern New Mexico is associated with sand shinnery oak (~lercus havardii) rangelands. Within prairie-chicken range in west Texas and eastern New Mexico, sand shinnery oak has become a nuisance to many cattle producers. Because shinnery oak can t effectively compete with grasses, reducing grass production ,f and stocking capacity, it is considered undesirable by many f ranchers (Pettit 1979). The herbicide tebuthiuron (N-[5- (l,l-dimethylethy1)-1,3,4-thiadiazol-2-yl]-N,N'- dimethylurea) has been used in west Texas and eastern New Mexico to control shinnery oak and improve grass production. While tebuthiuron effectively controls shinnery oak, questions exist concerning the effects of shinnery oak control on lesser prairie-chickens. Changes in habitat, resulting from tebuthiuron use could affect food supplies, and therefore body condition of lesser prairie-chickens. If 45 46 habitats do not provide sufficient nutrients and energy levels for birds, their condition declines and reproduction may be hampered (Breitenbach ~ al. 1963). Male birds are subject to weight loss and lessened condition from the stress of obtaining and defending mates and territories (Raitt and Ohmart 1966, West and Meng 1968, Anthony 1970, Roseberry and Klimstra 1971). Although condition normally declines during breeding (West 1968, West and Meng 1968), poor foraging habitat could worsen the situation. Females are especially prone to poor condition during nesting and incubation, and require proper foraging habitat to successfully produce young (Scott 1973, Kendeigh ~ al. 1977). Labisky and Jackson (1969) noted that hen ring-necked pheasants (Phasianus colchirnls) lost up to 20% of their original body weight during egg production. If proper foods are not available to female galliforms, their condition may worsen to a point where clutch size, renesting ability, and survival potential are adversely affected (Breitenbach ~ al. 1963, Barrett and Bailey 1972). The objective of this study was to evaluate and compare body condition (lipid, ash, water, and protein levels) of lesser prairie-chickens in tebuthiuron-treated and untreated sand shinnery oak rangelands. 47 Study Area Field work was conducted in Cochran and Yoakum Counties of Texas and Lea County of New Mexico. The study area is located at the southern portion of the Southern High Plains (Turner d al... 1974). Mean annual precipitation is 41 em and over 80% of the moisture occurs between May and October during thunderstorms (Dittemore and Hyde 1960, Newman 1960, Turner d al. 1974). Range cattle production is the major land use (Newman 1960). The area is currently dominated by shinnery oak, with less frequent occurrences of sand sagebrush (Artemisia filifolia), sand dropseed (Sporobolus cryptandrns), purple threeawn (Ad st ida pllrpurea), and broom snakeweed (Xanthocephalnm sarothrae) (Dittemore and Hyde 1960, Pettit 1979) . Methods Lesser prairie-chickens were collected on tebuthiuron- ~ .... treated and untreated control plots by shooting from 27 May- r 3 July during 1984 and 1985 to assess treatment impacts immediately following breeding. Vegetation in untreated control plots was dominated by extensive stands of shinnery oak (see Chapter 1). Vegetation on treatment plots was primarily composed of grasses which had replaced shinnery oak. Tebuthillron-treated pastures previously had been treated with the herbicide between 1979 and 1983 at a rate of 0.56 kg/ha. Collected birds were sexed according to a 48 plumage characteristics and internal examination (Edminster 1954, Copelin 1963, Henderson d.al. 1967). Birds were weighed to the nearest 0.01 g and frozen for later analysis. Liver weights of birds collected in 1985 were recorded to the nearest 0.01 g. Liver weights of birds collected in 1984 were not recorded. The entire feathered carcass (minus ingesta and feces) was sectioned and processed twice in an electric meat grinder. The homogenate was weighed, and forced-air oven (60 0 C) or freeze-dried to constant weight. The homogenate was reweighed to calculate the water content of the carcass, and reground. Fat (lipid) was extracted from 5-9 g samples of the dried homogenate using a Soxhelt apparatus and petroleum ether solvent for 40-41 hours (Horwitz 1980) The ether was then evaporated and the sample reweighed to the nearest 0.0001 g. The fat content is expressed on a fresh weight basis (g), and as a percentage of the wet carcass weight (carcass weight=body weight-gastrointestinal contents). Ash was determined by combusting duplicate 1-5 g samples of the dried, ground carcass in a muffle furnace at 600 0 C. The maximum allowable variation between duplicate samples was 1.5%. If variation exceeded 1.5%, additional trials were conducted until variation fell within the acceptable range. Ash-free lean dry weight (AFLD), an index of protein, was obtained by subtracting water, ash, and fat. 49 Data were analyzed using a 2x2 factorial analysis of variance by sex with treatment and year of collection as independent factors. Because data were not balanced, least square means rather than observed means were analyzed. Data were tested for normality using a Shapiro-Wilk W test. A I Bartlett's test was used to test for homogeneity of variances (Steel and Torrie 1980). When treatment variances were heterogeneous (as indicated by a significant Bartlett's test), treatments were compared following the approach of Milliken and Johnson (1984), who recommended using a weighted cOmbination of heterogeneous error terms. Interactions were analyzed using a Fisher's protected least significant difference test (FLSD) on the least square means. All tests were considered significant at £<0.05. Results Body Weights Body weights of males were 5.8% higher in untreated plots than in treated plots (Tables 3.1 and 3.2). Females displayed similar relationships, although they were not significant (Tables 3.3, 3.4). Carcass Components and Liver Wejghts There was 72.0% more fat (weight) in male lesser prairie-chickens collected from untreated shinnery than in those collected from treated plots (Table 3.2). A treatment*year interaction was also noted. Males collected 1&1 1iI'l"""~ " ""-'" " ... ,~ l' :"" '<;~"""',...:' 1\Y~?, ~;,iF;: ~~'''~,H:-;; !-f,?J Table 3.1. F-va1ues from 2-way analysis of variance (ANOVA) of body weight (BW), liver weight, and carcass components of male lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands during summer 1984-85. Source of variation df BW Fat % Fat AFLD a Ash Water Liverb Treatment 1 4.50' 32.37** 30.96** 2.69 0.34 1.65 0.58 Year 1 0.58 0.26 0.09 7.54 ** 10.71** 12.40** Treatment*Year 1 2.20 4.31* 3.69 4.04 0.7B 2.21 Errorc 33d 3301.94 26.33 O. ,55 165.11 7.00 1382.28 5.81 a Ash-free lean dry weight. b No livers were collected in 1984. c Mean squared errors. d Error degrees of freedom for ash=17; for liver weight=21. * £<0.05. ** £<0.01. (J> o -',--.-- ~ ---...... - .~"" "",",;,,~:!,. .. _. . ;'::"~ 'ciP''4~~" .~ Table 3.2. Comparison of body weight, liver weight, and carcass components (g) of male lesser prairie-chickens collected 27 May-3 July 1984-1985 from tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico. Values 'are expressed as least square means ± SE. variable Treated Untreated Means Body wt. 697.2 ± 23.46 768.5 ± 20.32 732.8A ± 15.52 Fat* 1l.7aA± 2.09 25.4bA ± 1. 81 18.5 ± 1. 39 1984 Water 403.1 ± 15.18 438.6 ± 13 .14 420.8A ± 10.03 Ash 28.9 ± 1. 08 28.6 ± 0.94 28.7A ± 0.71 AFLD 158.5 ± 5.24 174.7 ± 4.54 166.6A ± 3.47 % Fat 1.9 ± 0.30 3.8 ± 0.26 2.9A ± 0.20 1,iver wt. U1..... '~"~""-~'.-,,~~.,.' ,~ " '~,'j:,:" "'?';;'\ >:;:.Jt :';' "J;' "~:r,;:,Z,;:~ :";)[. ;,\,,~~h!£, :,~~,~i~1.~~~;~:\itj,[;~j;ttG;~!~~&:f,i~, Table 3.2. Continued. Variable Treated Untreated Means Body wt. 741. 6 ± 15.36 754.2 ± 19.15 747.9A ± 12.28 Fat* 16.2aA± 1. 37 22.6bA ± 1. 71 19.4 ± 1.10 1985 Water 467.2 ± 9.94 464.6 ± 12.39 465.9B ± 7.94 Ash 31.1 ± 0.71 32.4 ± 0.88 31. 8B ± 0.56 AFLD 179.6 ± 3.43 177.9 ± 4.28 178.8B ± 2.74 % Fat 2.3 ± 0.20 3.2 ± 0.25 2.8A ± 0.16 Liver wt. 9.4 ± 0.64 8.6 ± 0.80 9.0 ± 0.51 (J1 N "--.~ '--,---. i" ...... J', .. , fJ:litti~i!~:~;.:i::~t£II?~lI~~ ~ ... Table 3.3. F-values from 2-way analysis of variance (ANOVA) of body weight (BW), liver weight, and carcass components of female lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands during summer 1984-85. Source of variation df BW Fat % Fat AFLDa Ash Water Liverb Treatment 1 1.15 4.14 5.21* 2.01 0.47 0.57 0.63 Year 1 0.32 0.02 0.05 3.44 0.08 4.31 Treatment*Year 1 0.82 0.89 1.12 0.89 0.14 0.12 Errorc lld 3966.12 100.06 2.20 138.50 17.39 1285.80 4.45 a Ash-free lean dry weight. b No livers were collected in 1984. c Mean squared errOrs. d Error degrees of freedom for body weight=14; for liver weight=10. * 1'.<0.05. en ", ~.-.~-~-- ;, "";,!cj. ·01j i;!idi:;~'J'i;;::~:;:;I;;i.~l;;:f'!i;;Bma:~,~ Jfrl '~.~"" ""."be· """"'''''' Table 3.4. Comparison of body weight, liver weight, and carcass components (g) of female lesser prairie-chickens collected 27 May-3 July 1984-1985 from tebuthiuron treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico. Values are expressed as least square means ± SE. Variable Treated Untreated Means Body wt. 583.3 ± 36.36 650.0 ± 44.53 616.7A ± 28.74 Fat 9.1 ± 7.07 26.5 ± 7.07 17.8A ± 5.00 1984 Water 332.9 ± 25.36 356.0 ± 25.36 344.4A ± 17.93 Ash 24, 6 ± 2.95 27 .2 ± 2.95 25.9A ± 2.08 AFLD 133.8 ± 8.32 150.1 ± 8.32 142.0A ± 5.88 % Fat 1.8 ± 1. 05 4.7 ± l. 05 3.2A ± 0.74 Liver wt. en en ~'-.~ ...... ~ ...... ~...... "...... ~." ...... ~~ ...... ~ ...... ~~ ...... ~ ...... ~."' ...... "'·"="·C=·"=~'''''''''''''·''7'''''",c,,,,,,,,,,~,,,,,,,,,,,,",,.,: ... ,,,,,,,,, ... ,,;.,,,,~,,,,,,, Table 3.4. Continued. variable Treated Untreated Means Body wt. 632.8 ± 23.80 638.5 ± 25.71 635.6A ± 17.52 Fat 15.3 ± 4.47 2l.7 ± 4.08 18.5A ± 3.03 1985 Water 383.6 ± 16.04 392.3 ± 14.64 388.0A ± 10.86 Ash 26.2 ± 1. 86 27.0 ± l. 70 26.6A ± 1.26 AFLD 153.1 ± 5.26 156.4 ± 4.80 154.7A ± 3.56 % Fat 2.5 ± 0.66 3.6 ± 0.60 3.0A ± 0.45 Liver wt. 8.0 ± 0.86 7.0 ± 0.86 7.5 ± 0.61 V> 0\ ":""','"'' 1,"::'';'-',_ • ""::r'~~' "''''ii'' ~',1' Table 3.4. Continued. Variable Treated Untreated Means Body wt. 608.1a ± 21.73 644.2a ± 25.71 Fat 12.2a ± 4.18 24.1a ± 4.08 Means Water 358.3a ± 15.00 374.1a ± 14.64 Ash 2S.4a ± 1. 74 27.1a ± 1. 70 AFLD 143.Sa ± 4.92 153.2a ± 4.80 % Fat 2.1a ± 0.62 4.1b ± 0.60 Liver wt. S.Oa ± 0.86 7.0a ± 0.86 1 For a given variable, means within a row followed by the same lower case letter are not significantly different (E>0.05). 2 For a given variable, means within a column followed by the same upper case letter are not significantly different (£>0.05). 3 Where letters are not present, FLSD tests were not conducted because there was not a significant (£<0.05) F test. i (J1 I -J I .. "'" ...... 'i' ;'(!!.,.,'!.. ..f5~:2:::j':;;·7;r?:;,i!f;~£,:i;~,,1,:!![0:i!·l;t~5int~!\1 58 from untreated plots had 117.6% mOre fat than males collected from treated plots (£<0.01) during 1984. However, males collected from untreated plots had only 39.3% more fat than males collected from treated plots during 1985. Female lesser prairie-chickens exhibited the same trends as males (Table 3.4). Females collected in untreated areas contained 97.4% more fat by weight than females collected in treated sites, but differences were not significant (£>0.05). Among males and females, percent fat was higher from birds collected on untreated sites than from treated plots (Tables 3 .2 and 3. 4) . Male prairie-chickens collected during 1985 contained 10.7% more water (£<0.01) than males collected in 1984. Females displayed the same trends as males. Ash was 10.5% higher (£<0.01) among male prairie- chickens collected during 1985 than among males collected during the 1984 collection period (Table 3.2). Female prairie-chickens displayed similar results (Table 3.4). Among male lesser prairie-chickens, AFLD did not show a significant treatment effect (Table 3.1). However, AFLD weight was greater in birds collected in 1985 than in birds collected in 1984 (Tables 3.1 and 3.2). Differences in AFLD between years were more pronounced for males collected in treated plots than in untreated plots (£<0.053). Females displayed the same trends as males. Liver weights of lesser 59 prairie-chickens did not differ between treatment types for either sex (Tables 3.1, 3.3). Discussion Sell (1979) reported that body weights of male lesser prairie-chickens from shinnery oak rangelands in Texas, May- ! July, were 750 g, while females weighed 699 g. Similar to •c f; , Sell, we found that body weights of prairie-chickens r collected from untreated shinnery 27 May-3 July were 761 g rf and 644 g for males and females, respectively. Birds would be expected to weigh less during summer due to stresses f associated with nesting, incubating, and brooding in females and territorial defense in males. The most obvious reason for the differences between treatments in body weights of prairie-chickens appears to be fat content. Male prairie-chickens contained 3.5% and 2.1% body fat in untreated and treated plots, respectively. Percent fat found in females was 4.1% in untreated plots and 2.1% in treated plots. Differences among females for several variables may not have been detected due to the small sample size. Percent fat present in lesser prairie- chickens during 1984 and 1985 was similar to percentages found in other tetraonids. Studies with willow ptarmigan (Lagopus 1agQPus) have found that average fat percent falls within a range of approximately 2-5%, depending upon season and locality (West and Meng 1968, Myrberget and Skar 1976, Il 21 ID 60 Brittas and Marcstri:im 1982, Thomas 1982). Rock ptarmigan (Lagopus mntns) and ruffed grouse (Bonasa umbel Ius) also have similar lipid levels (Thomas ~ ai. 1975, Mortensen ~ QJ... 1985). Differences between treatments in prairie-chicken fat content are probably associated with differences in diet. Norman and Kirkpatrick (1984) noted that in ruffed grouse, fat deposition was due to a high dietary energy intake resulting from consumption of high-carbohydrate foods, such as soft and hard fruits. Acorns accounted for most of the hard fruits eaten. Similarly, the greater fat content in lesser prairie-chickens from untreated shinnery is probably the result of shinnery oak acorn consumption. Within untreated pastures, shinnery oak acorns represented 59.8% and 35.8% of the prairie-chicken summer diet in 1984 and 1985, respectively (see chapter 2). Shinnery oak acorns were absent from the summer diets of prairie-chickens collected from tebuthiuron-treated plots during 1984 and 1985. Within untreated shinnery, fat content of male prairie chickens decreased from 1984 to 1985. During the same time period, fat content of males from treated pastures increased. The decrease in fat content from 1984 to 1985 is probably the result of a decrease in acorn consumption during the same period (see chapter 2). The increase in fat content of males in treated plots from 1984 to 1985 may be 61 due to a decrease in foliage consumption, as well as an increase in seed consumption. Norman and Kirkpatrick (1984), when looking at total non structural carbohydrates of ruffed grouse foods, found that while total nonstructural carbohydrate levels were positively related to the percentage of dry weight of fruits, they were inversely related to the percentage of leaves of herbaceous plants. Thomas (1982) also suggested that eating foods with low digestibilities, in addition to the increased time and energy spent feeding, may be detrimental to fat deposition in willow ptarmigan. AFLD (protein) weight of male lesser prairie-chickens was greater in 1985 than in 1984. The cause of this difference is probably the result of dietary differences. Total insect consumption by prairie-chickens increased from 1984 to 1985. Animal foods, such as insects, provide an important source of protein for birds (Welty 1982). Within untreated plots, insect consumption by prairie-chickens r increased from 18.7% to 31.7% between 1984 and 1985 (see j chapter 2). During the same period, consumption of insects J in treated plots increased 24 times. The avian liver serves several functions. These I include storage of lipids and glycogen, intermediary metabolism, synthesis of proteins and glycogen, and production of bile to break down fats (Farner 1960). I Changes in liver weights can result from several variables !1 I 1. 62 (Drobney 1984). Liver weight increases have been associated with periods of increased fat deposition (Drobney 1980, Mortensen ~ al. 1983). Increased liver weight has also occurred in relation to increased food intake, and metabolism level fluctuations in lesser snow geese (~ caerlllescens caerulescens) (Ankney 1977) and wood ducks (.lii.z. sponsa) (Drobney 1984). However, treatment or dietary differences were not manifested with significantly different liver weights in this study. Cope] lJsiQDS Lesser prairie-chickens have poorer body condition during summer in tebuthiuron-treated plots than in untreated shinnery oak sites. Decreased fat and protein levels of prairie-chickens in tebuthiuron-treated rangelands "appear to correspond to dietary changes. Condition of birds may suffer not only from lack of high quality foods, but also from the additional energy expenditure of increased feeding to compensate for that void. As a result of poorer condition, prairie-chickens in treated areas may be affected more by stressful situations, including molt, thermoregulation, and reproductive activities, than their counterparts in untreated shinnery. Therefore, maintaining , areas of untreated shinnery oak with treated areas would most likely be more beneficial to lesser prairie-chickens 63 than extensive tebuthiuron treatments on the Southern High Plains. i t I'-- i- CHAPTER IV MANAGEMENT RECOMMENDATIONS Areas of untreated shinnery oak should be maintained because lesser prairie-chickens find several important foods, including acorns, in shinnery-dominated areas (see Chapter 2). Acorn consumption probably allows prairie- chickens feeding in untreated shinnery to attain higher body fat levels than birds feeding in pastures without shinnery oak, at least in years of adequate acorn production (see Chapter 3). However, the increased grass production in treated plots appears to provide better concealing cover for prairie-chickens than that found in untreated shinnery (see Chapter 1) . We recommend treating only strips or patches of sand shinnery oak with tebuthiuron at rates between 0.4 kg/ha and 0.6 kg/ha. An interspersion of the 2 habitat types would provide lesser prairie-chickens with important food items and shade found in untreated areas; along with additional foods and the superior escape and pos~ible nesting cover of treated sites, provided that overgrazing is avoided. Preferably, strips or patches should be approximately 0.8 km (0.5 mile) wide. Areas of this size would be small enough to allow a large proportion of prairie-chickens in the area to utilize both tebuthiuron-treated and untreated areas; and 64 65 large enough to provide sufficient quantities of each habitat type to prairie-chickens. Application costs should be lower than with more extensive treatments, because both application (flying) time and herbicide quantities used would be reduced. Treating strips smaller than this would not be practical because application time and effort increase when several small strips are treated. In situations where treating 0.8 km wide strips or patches is not practical, we still suggest preserving scattered patches of untreated shinnery within treated pastures and/or leaving untreated pastures among treated pastures. Shinnery oak on dunes and areas surrounding blowouts should not be treated, since few herbaceous plants OCCur on these structures, and removal of shinnery would result in excessive wind erosion (McIlvain and Armstrong 1958). Landowners would most likely benefit from leaving at least some remnants of untreated shinnery. Shinnery oak foliage is a more reliable forage source for livestock than grasses and forbs during periods of drought (Pettit 1979) In conclusion, if sand shinnery oak control occurs on a limited basis, and sufficient quantities of untreated shinnery are preserved, lesser prairie-chicken populations should not be adversely affected. £ LITERATURE CITED Ankney, C. D. 1977. Feeding and digestive organ size in breeding lesser snow geese. Auk 94:275-282. Anthony, R. 1970. Ecology and reproduction of California quail in southeastern Washington. Condor 72:276-287. Barrett, M. W., and E. D. Bailey. 1972. Influence of metabolizable energy on condition and reproduction of pheasants. J. Wildl. Manage. 36:12-23. Borror, D. J., B. M. Delong, and C. A. Triplehorn. 1981. An introduction to the study of insects. 5th ed. Saunders College Publishing. Philadelphia, Penn. 827pp. Breitenbach, R. P., C. L. Nagra, and R. K. Meyer. 1963. Effect of limited food intake on cyclic annual changes in ring-necked pheasant hens. J. wildl. Manage. 27:24- 36. Brittas, R., and V. Marcstrom. 1982. Studies in willow Grouse Laqoplls lagopus of some possible measures of condition in birds. Ornis Fennica 59:157-169. Burnham, K. P., D. R. Anderson, and J. L. Laake. 1980. Estimation of density from line transect sampling of biological populations. Wildl. Monogr. 72. 202pp. Campbell, H. 1972. A population study of lesser prairie chickens in New Mexico. J. Wildl. Manage. 36:689-699. Cannon, R. W., and F. L. Knopf. 1981. Lesser prairie chicken densities on shinnery oak and sand sagebrush rangelands in Oklahoma. J. Wi1dl. Manage. 45:521-524. Copelin, F. F. 1963. The lesser prairie chicken in Oklahoma. Okla. wildl. Conserv. Dept. Tech. Bull. 6. 58pp. Correll, D. S., and M. C. Johnston. 1979. Manual of the vascular plants of Texas. Univ. Texas at Dallas, Richardson. 1881pp. Crawford, J. A., and E. G. Bolen. 1976. Fall diet of lesser prairie chickens in west Texas. Condor 78:142- 144. 66 s 67 Davis, C. A., T. Z. Riley, R. A. Smith, H. R. Suminski, and M. J. Wisdom. 1979. Habitat evaluation of lesser prairie chickens in eastern Chaves County, New Mexico. Dept. of Fisheries and wildl. Sci., N.M. State Univ. Agric. Exp. Stn., Las Cruces. 141pp. Dittemore, W. H., and H. W. Hyde. 1960. Soil survey of Yoakum County, Texas. U.S. Gov. Print. Off., Washington, D.C. Ser. 1960. No. 15. 53pp. Doerr, T. B., and F. S. Guthery. 1980. Effects of shinnery oak control on lesser prairie chicken habitat. Pages 59-63. in P. A. Vohs, Jr. and F. L. Knopf, eds. Proc. of prairie grouse symp. Okla. State Univ., Stillwater . . , and 1983a. Effects of tebuthiuron on ------=--lesser prairie-chicken habitat and foods. J. Wildl. Manage. 47:1138-1142. _____ ., and 1983Q. Food selection by lesser prairie chickens in northwest Texas. Southwestern Nat. 28:381-383. Drobney, R. D. 1980. Reproductive bioenergetics of wood ducks. Auk 97:480-490. 1984. Effect of diet on visceral morphology of breeding wood ducks. Auk 101:93-98. Edminster, F. C. 1954. American game birds of field and forest. Charles Scribner's Sons, New York, N.Y. 490pp. Emmerich, W. E. 1985. Tebuthiuron-environmental concerns. Rangelands. 7:14-16. Evans, R. A., and R. M. Love. 1957. The step-point method of sampling--a practical tool in range research. J. Range Manage. 9:208-212. Farner, D. S. 1960. Digestion and the digestive system. Pages 411-467. in A. J. Marshall, ed. Biology and comparative physiology of birds. Vol. 1. Academic press, New York, N.Y. 518pp. Gould, F. W. 1969. Texas plants--a checklist and ecological summary. Texas Agric. Exp. Sta. Misc. Pub1. 585. Rev. 121pp. 68 Henderson, F. R., F. W. Brooks, R. E. Wood, and R. B. Dahlgren. 1967. Sexing of prairie grouse by crown feather patterns. J. Wildl. Manage. 31:764-769. Hoffman, D. M. 1963. The lesser prairie chicken in Colorado. J. wild1. Manage. 27:726-732. Hollander, M., and D. A. Wolfe. 1973. Nonparametric statistical methods. John Wiley and Sons, New York, N.Y. 503pp. Horwitz, W., ed. 1980. Official methods of analysis of the Association of Official Analytical Chemists. 13th ed. Assoc. Off. Anal. Chem. Washington, D.C. 1018pp. Jackson, A. S., and R. DeArment. 1963. The lesser prairie chicken in the Texas panhandle. J. Wildl. Manage. 27:733-737. Johnson, R. R. 1976. Elementary statistics. 2nd ed. Duxbury Press, North Scituate, Mass. 550pp. Jones, R. E. 1963. Identification and analysis of lesser prairie chicken habitat. J. Wildl. Manage. 27:757-778. 1964. Habitat used by lesser prairie chickens for feeding related to seasonal behavior of plants in Beaver County, Oklahoma. Southwestern Nat. 9:111-117. Kendeigh, S. C., V. R. Dol'nick, and V. M. Gavrilov. 1977. Avian energetics. Pages 127-204. in J. Pinowski and S. C. Kendeigh, eds. Granivorous birds in ecosystems. Cambridge Univ. Press, London. 431pp. Laake, J. L., K. P. Burnham, and D. R. Anderson. 1974. User's manual for program TRANSECT. Utah State Univ. Press, Logan. 26pp. Labisky, R. F., and G. L. Jackson. 1969. Production and weights of eggs laid by yearling, 2-, and 3-year-old pheasants. J. wildl. Manage. 33:718-721. Lawson, P. B. 1922. The membracidae of Kansas. Kan. Univ. Sci. Bull. 14:31-110. /Leopold, A. S. 1953. Intestinal morphology of gallinaceous birds in relation to food habits. J. Wildl. Manage. 17:197-203. 69 Lutz, F. E. 1921. Field book of insects. G. P. Putnam's Sons. New York, N.Y. 562pp. MCIlvain, E. H., and C. G. Armstrong. 1958. Shinneryoak control by aerial spraying in the Southern Great Plains. Southern Great Plains Field Sta., Woodward, Okla. 5pp. Milliken, G. A., and D. E. Johnson. 1984. Analysis of messy data. Volume I: Designed experiments. Van Nostrand Reinhold Co. New York, N.Y. 473pp. Mortensen, A., S. Unander, M. Kolstad, and A. S. Blix. 1983. Seasonal changes in body composition and crop content of Spitzbergen ptarmigan Lag-opus mutus hyperboreus. Ornis Scand. 14:144-148. ______~_.' E. S. Nord0y, and A. S. Blix. 1985. Seasonal t- changes in the body composition of the Norwegian Rock " Ptarmigan Lag-opus mutus. Ornis Scand. 16:25-28. Moss, R. 1972. Effects of captivity on gut lengths in red grouse. J. wi1dl. Manage. 36:99-104. 1974. Winter diets, gut lengths, and interspecific competition in Alaskan ptarmigan. Auk 91:737-746. 1983. Gut size, body weight, and digestion of winter foods by grouse and ptarmigan. Condor 85:185- 193. Myrberget, S., and H. J. Skar. 1976. Fat and calorific content of Willow Grouse in autumn and winter. Norw. J. Zool. 24: 41-45. National Oceanic and Atmospheric Administration. 1984-1986. Climatological data: New Mexico, monthly summaries. Natl. Climatic Cent., Asheville, N.C. National Oceanic and Atmospheric Administration. 1984-1986. Climatological data: Texas, monthly summaries. Natl. Climatic Cent., Asheville, N.C. Newman, A. L. 1960. Soil survey of Cochran County, Texas. U.S. Gov. Print. Off., Washington, D.C. Ser. 1960. No. 17. 80pp. 70 Norman, G. W., and R. L. Kirkpatrick. 1984. Foods, nutrition, and condition of ruffed grouse in southwestern Virginia. J. Wildl. Manage. 48:183-187. Pettingill, O. S., JR. 1970. Ornithology in laboratory and field. 4th. ed. Burgess Publishing Co., Minneapolis, Minn. 424pp. Pettit, R. D. 1979. Effects of picloram and tebuthiuron pellets on sand shinnery oak communities. J. Range Manage. 32:196-200. Prevett, J. P., I. F. Marshall, and V. G. Thomas. 1979. Fall foods of lesser snow geese in the James Bay region. J. wildl. Manage. 43:736-742. Raitt, R. J., and R. D. Ohmart. 1966. Annual cycle of reproduction and molt in gambel quail of the Rio Grande Valley, southern New Mexico. Condor 65:541-561. Roseberry, J. L., and W. D. Klimstra. 1971. Annual weight cycles in male and female bobwhite quail. Auk 88:116- 123. Scott, M. L. 1973. Nutrition in reproduction-direct effects and predictive functions. Pages 46-59. in D. S. Farner, ed. Breeding biology of birds. Natl. Acad. Sci., Washington, D.C. 515pp. Sell, D. L. 1979. Spring and summer movements and habitat use by lesser prairie chicken females in Yoakum County, Texas. M.S. Thesis. Texas Tech Univ., Lubbock. 42pp. Sperry, O. E., J. W. Dollahite, G. O. Hoffman, and B. J. Camp. 1964. Texas plants poisonous to livestock. Texas Agric. Exp. Sta. Bull. 1028. 59pp. "i '-'-~ - . I Steel, R. G., and J. H. Torrie. 1980. Principles and procedures of statistics: a biometrical approach. 2nd ed. McGraw-Hill Book Co., New York, N.Y. 633pp. Swanson, G. A., and J. C. Bartonek. 1970. Bias associated with food analysis in gizzards of blue-winged teal. J. Wildl. Manage. 34:739-746 . . , G. L. Krapu, J. C. Bartonek, J. R. Serie, and D. ----~H~.-Johnson. 1974. Advantages in mathematically weighting waterfowl food habits data. J. wildl. Manage. 38:302-307. 71 Taylor, M. A. 1978. Fall and winter movements and habitat use of lesser prairie chickens. M.S. Thesis. Texas Tech Univ., Lubbock. 52pp. ______., and F. S. Guthery. 1980a. Fall-winter movements, ranges, and habitat use of lesser prairie chickens. J. Wildl. Manage. 44:521-524. _____ ., and ---:c-,--- 1980l;l. Status, ecology, and management of the lesser prairie chicken. USDA For. Servo Gen. Tech. Rep. RN-77. 15pp. Rocky Mountain Forest and Range Experiment Station, Fort Collins, Colo. Thomas, V. G. 1982. Energetic reserves of Hudson Bay willow ptarmigan during winter and spring. Can J. Zool. 60:1618-1623 . . , H. G. Lumsden, and D. H. Price. 1975. -----A~sp-ects of the winter metabolism of ruffed grouse (Bonasa umbellus) with special reference to energy reserves. Can. J. Zool. 53:434-440. Turner, M. T., D. N. Cox, B. C. Mickelson, A. J. Roath, and C. D. Wilson. 1974. Soil survey of Lea County, New Mexico. U.S. Gov. Print. Off., Washington, D.C. 89pp. Uvarov, B. P. 1931. Insects and climate. Trans. of the Entomological Society of London. 79:1-247. Welty, J. C. 1982. The life of birds. 3rd ed. Saunders College Publishing. Philadelphia, Penn. 754pp. West, G. C. 1968. Bioenergetics of captive willow ptarmigan under natural conditions. Ecology 49:1035- 1045. ------7.' and M. S. Meng. 1968. Seasonal changes in body weight and fat and the relation of fatty acid composition to diet in the willow ptarmigan. Wilson Bull. 80:426-441. APPENDIX A VEGETATION OF THE STUDY AREA 72 Table A.l. Percent basal composition of vegetation on tebuthiuron-treated and untreated sand shinnery oak rangelands during fall 1985 and spring 1986. Fall 1985 Spring 1986 Species Treated Untreated Treated Untreated Grasses Aristida purpurea 21.5 8.6* 30.0 7.1** Schizachvrium scoparium 17.2 7.9 19.9 17.7 Paspalum setaceum 9.1 3.6* 4.0 0.1* Sporobolus ~rvpiandrus 9.0 3.7 7.4 2.5 Bouteloua hirsuta 7.0 2.6 8.2 3.6 Munroa squarrosa 3.3 0.0* 0.0 0.0 AndroPQgQn hallii 4.7 1.3 2.0 1.3 Leptoloma cognatum 3.1 2.9 0.0 0.0 EraqrQstis_ Qxvlepis 2.5 1.1 0.7 0.5 Bouteloua curtipendula 1.4 1.1 0.0 0.0 Aristida longiseta 0.0 2.7 0.0 0.0 '-< Total Grasses 78.8 35.5** 72 .2 32.8** -J w Table A.1. Continued. Fall 1985 Spring 1986 Species TreateGi Untreated Treated Untreated Grass-like Cyperus uniflorus 2.5 4.2 0.2 0.0 Cyperus schweinitzii 0.0 0.6 0.0 0.0 Total Grass-like 2.5 4.8 0.2 0.0 Forbs Erioqonum annuum 4.7 0.4* 0.2 0.1 HeterQtheca 1atifo1ia 3.9 0.1* 0.0 0.0 ChamaesarachB sp. 0.0 0.0 8.8 0.0** Lithospermum incisum 0.0 0.0 4.6 0.2* Mirabilis linearis 1.8 0.2 0.0 0.0 Erigeron modestus 1.3 3.5 0.0 0.0 Conyza canadensis 1.3 0.0 0.0 0.0 Xanthocephalum sarothrae 1.0 2.7 0.0 0.0 Crv~tantha iamesii 0.2 0.0 2.5 0.1 -.l ol> Table A.1. Continued. Fall 1985 Spring 1986 Species Treated untreated Treated Untreated Senecio riddellii 0.0 0.0 3.1 0.2 Calylophus serrulatus 0.0 0.0 3.0 0.8 Artemisia caudata 0.0 0.0 1.0 0.1 Oenothera rhorobipetala 0.4 0.0 0.1 0.2 Thelesperma megapotamicum 0.4 0.1 0.0 0.1 Cycloloma atriplicifolillm 0.4 0.0 0.0 0.0 Linum rigidum 0.3 0.0 0.0 0.0 Evolvulus nuttallianus 0.2 0.2 0.0 0.0 Palafoxia sphacelata 0.2 0.0 0.0 0.0 Euphorbia missurica 0.2 0.0 0.0 0.0 Ambrosia psilostachya 0.1 0.8 0.0 0.0 EupbQrbia sp. 0.1 0.1 0.0 0.0 Dithyrea wislizenii 0.0 0.4 0.1 0.0 CQmmel~na erecta 0.0 0.1 0.0 0.0 -..J en '-'''''''' ...... ~".". ''"-'"~''''''''' .-~-..,,-.,~~ .. --.~-~'--~,~.,...,-.-, ...... ~-~~~~-~, " 1M ,- .; p- A" ;00'-, '""' it ": :.:;;" .'/,:'e:'; "":':{~i~{:tt~;lL;:::' ~.';I'.'~:1~?;;:\t, '''', Table A.1. Continued. Fall 1985 Spring 1986 Species Treated Untreated Treated Untreated Astragalus mollissimus 0.0 0.0 0.1 0.1 Paronychia jamesii 0.0 0.0 0.2 0.0 Schrankia uncinata 0.0 0.1 0.0 0.0 Unidentified 0.0 0.1 0.0 0.0 Unidentified 0.3 0.0 0.0 0.0 Unidentified 0.0 0.1 0.0 0.0 Unidentified 0.0 0.1 0.0 0.0 Unidentified 0.1 0.0 0.0 0.0 Total Forbs 16.9 9.0** 23.7 1. 9** -.l '" ,..--, ...... -~-~ •..• -,.;+"' •. ,....-,-~...,...,." •. -.,...... ,.."...,"'"'"""...---",..-...,~....,."."..,.. ~ t."'. ""Fn,.. ,,1M,. ,."if ~""" (~i<'<,_ "","Fl.'''' ,;til ;;oh~""'~·,?fi!I; .._ .. ;;,:;;:;~ii!F.J.@A ·.M."i~)!I , :\~ Table A.l. continued. Fall 1985 Spring 1986 Species Treated Untreated Treated Untreated Shrubs Ouercus havardii 0.7 47.6** 1.6 63.9** Artemisia filifolia 0.1 1. 8* 1.0 0.9 Opuntia polyacantha 0.6 0.7 0.3 0.5 Yucca sp. 0.2 0.6 0.8 0.2 Total Shrubs 1.8 50.7** 3.9 65.3** * £<0.05 between treatments within seasons. ** £<0.01 between treatments within seasons. -.l -.l ~ I,J ~'. ,'1\ -,-": APPENDIX B MORPHOLOGICAL MEASUREMENTS OF LESSER PRAIRIE-CHICKENS 78 Table B.1. Body measurements and percent fat of 55 lesser prairie-chickens collected from tebuthiuron-treated and untreated sand shinnery oak rangelands of west Texas and eastern New Mexico. Collection Treatment Sex Body Body Winga Percentb Date Type Weight Length Length Fat (g) (em) (em) 6/11/84 Treated F 610.00 35.5 20.4 6/11/84 Untreated F 665.00 40.0 20.6 5.57 6/11/84 Untreated M 660.00 38.8 20.5 5.29 6/18/84 Untreated M 830.00 41. 0 20.6 3.55 6/18/84 Untreated M 732.79 39.9 20.6 4.10 6/18/84 Untreated M 765.00 41.1 21.0 3.53 6/18/84 Treated M 630.00 39.4 20.3 1. 55 6/18/84 Untreated M 795.00 39.9 20.5 4.41 6/18/84 Treated M 810.00 40.3 20.9 2.42 6/18/84 Treated M 695.00 37.8 19.8 2.65 6/27/84 Treated M 745.00 40.7 20.8 1. 41 6/27/84 Treated F 610.00 39.3 19.5 2.36 -.J '" I'L~~... '_."" __ ""_•. _ ».,._ .. _'<.~_._ ,"' '''''. __ '_' ___''~~''~'"~' __ '''''''''''''"'"' _.,,, .... -.. .""~ .'.,...... ~~ """""'""" ~ ~'7,"""'", -..,...,~ "'n''''',,,," m'--:"!'" -,-?,,~ ",:,,)-..,.~ ''''.,..".,7:," Table B.l. Continued. Collection Treatment Sex Body Body Winga Pereentb Date Type Weight Length Length Fat (g) (em) (em) ------ 7/ 1/84 Untreated M 758.00 40.0 20.1 4.34 7/ 1/84 Treated F 530.00 35.3 20.5 1. 20 7/ 1/84 Untreated M 897.00 42.1 20.1 2.74 7/ 1/84 Treated M 685.00 40.4 19.8 2.22 7/ 3/84 Treated M 618.00 41.0 21.2 1. 20 7/ 3/84 Untreated F 635.00 36.3 20.6 3.78 7/ 3/84 Untreated M 710.00 39.3 19.1 2.56 5/27/85 Treated F 586.44 39.0 21.2 1. 29 5/27/85 Treated F 550.80 38.5 20.1 5/27 /85 Treated M 774.24 40.5 21.6 2.54 5/27/85 Treated M 721.22 39.0 21.4 1.71 5/28/85 Treated M 729.79 40.1 21. 0 2.59 5/28/85 Untreated M 754.71 40.5 21. 8 2.96 00 0 D__ ,.<' ''"'" \ . <, ",f HE'. "~"",'" ¢, "'" '. '" Table B.1. Continued. Collection Treatment Sex Body Body Winga Pereentb Date Type Weight Length Length Fat (g) (em) (em) 5/28/85 Untreated M 746.12 39.5 22.0 3.61 5/29/85 Treated M 758.38 38.0 2l. 4 2.80 5/29/85 Treated M 713.60 40.1 2l.7 2.42 5/29/85 Treated M 71l.21 4l.0 2l.1 3.49 5/29/85 Untreated F 626.78 37.1 2l. 4 l. 39 5/29/85 Treated F 735.46 2l.2 5/30/85 Untreated F 645.18 37.1 20.6 4.64 5/30/85 Untreated F 622.67 37.7 20.4 4.79 5/30/85 Untreated M 771.66 38.7 21.4 2.21 5/30/85 Untreated M 689.00 39.6 21.2 4.30 5/31/85 Untreated F 582.04 36.5 21.1 2.74 5/31/85 Untreated M 725.56 40.5 20.8 3.13 5/31/85 Untreated M 859.57 40.8 20.8 3.47 OJ f-' . -,-~--,"",---~-.-.,-,~""---.------~~~.~.. -.-,..-~- ."'" ·",F. '" ';h,",(i,R4-"'i+ '" /,_ ''''''''''''''i@?FP%I, kJ&.,H.81.i,.& ," Table B.1. Continued. Collection Treatment Sex Body Body Winga Pereentb Date Type weight Length Length Fat (g) ---- (em) (em) 5/31/85 Treated M 737.62 40.5 21.5 1. 60 5/31/85 Treated M 860.39 42.0 21.8 2.40 6/ 1/85 Treated M 676.49 37.8 20.3 2.29 6/ 1/85 Treated M 740.77 40.5 21.1 1. 94 6/ 1/85 Treated M 770.15 40.5 21.4 3.85 6/ 1/85 Treated F 694.47 37.9 19.4 3.49 6/ 1/85 Treated M 781. 94 40.8 22.1 1. 63 6/ 7/85 Untreated M 72 6.63 41.0 21.0 3.55 6/ 8/85 Treated M 722.11 39.0 21. 6 2.05 6/ 9/85 Treated F 517.48 37.1 20.5 0.65 6/ 9/85 Untreated F 714.01 38.4 20.2 5.52 6/12/85 Treated F 642.35 38.1 20.9 3.14 6/14/85 Untreated F 640.07 37.0 21.3 2.34 (» '" -"'-"'-';"T"-''''''--',,-,,·, "":'","::'<"7:": Table B.lo Continued. Collection Treatment Sex Body Body Winga Percentb Date Type Weight Length Length Fat ( g) (em) (em) --- - -_.- 6/19/85 Untreated M 762.15 41. 5 21.6 2.32 6/20/85 Treated M 684.54 39.6 20.8 1. 22 6/20/85 Untreated M 752.74 39.5 20.9 3.71 6/26/85 Treated F 702.65 38.0 21.1 3.99 a Wing length measured to tip of the eighth primary. b Expressed as a percentage of the wet carcass weight. ro W Jj] PERHISSION TO COpy In presenting this thesis in partial fulfillment of the requirements for a master's degree at Texas Tech University, I agree that the Library and my major department shall make it freelY avail- able for research purposes. Permlssion to copy this thesis for scholarly purposes may be granted by the Director of the Library or my major professor. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my further written permission and that any user IMy be liable for copy- right infringement. 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