Iowa State College Journal of Science 27.4
Total Page:16
File Type:pdf, Size:1020Kb
WINTER BEHAVIOR OF THE RING-NECKED PHEASANT, PHASIANUS COLCHICUS, AS RELATED TO WINTER COVER IN WINNEBAGO COUNTY, IOWA1 CARROLL R. GRONDAHL 2 Iowa Cooperative Wildlife Research Unit Department of Zoology and Entomology Iowa State College Received January 8, 1953 Game managers generally acknowledge winter as a critical season in the life of the ring-necked pheasant, Phasianus colchicus, and they realize the importance of adequate cover in juxtaposition to a stable food supply, such as standing field corn, Zea mays. Also, it is recognized that long daily and/or weekly movements of pheasants on an area are, in part, an expression of the suitability of winter cover and food conditions (2, 7). The purposes of this study were (a) to obtain information regarding the winter behavior of ring-necked pheasants in relation to farm shelter belts and varying weather conditions, and (b) to contribute information for formulating management policies for this important game species. The investigations were conducted on 2,480 acres of the Winnebago Pheasant Research Area, Eden Township, Winnebago County, in north central Iowa from December 21, 1950, until June 1, 1951. METHODS Trapping operations were conducted at eight farm shelterbelts and one slough area with seven Ohio-type pheasant traps (6) during the period December 21, 1950, to March 3, 1951. The term farm shelterbelt as used in this paper denotes human plantings of trees adjacent to farm sites. An Iowa State Conservation Commission aluminum butt-end leg band, a colored plastic leg band (10), and a slightly modified Taber marker (8) were attached to each trapped bird for identification pur poses. Early in the study a route was established that covered 21 miles of roads on and surrounding the area. The route was laid out in such . a way that 17 miles were on roads circumscribing the area at distances 1 Journal Paper No. J-2228, Project No. 497, Iowa Agricultural Experiment Sta tion, Ames, Iowa. The Iowa State Conservation Commission, Iowa State College, the Wildlife Management Institute, and the U. S. Fish and Wildlife Service cooperating. 2 The author is indebted to Drs. E. L. Kozicky and G. 0. Hendrickson under whose leadership the investigation was conducted. Their contributions of time in the field, counsel, and encouragement were of unlimited value. The kindness, hospitality, and material help extended by Mr. and Mrs. 0. B. Christenson and the many other farm ers residing on the study area are gratefully recognized. [ 447] 448 CARROLL R. GRONDAHL up to 2.75 miles from the trap sites, while the remaining four miles were on roads traversing the area. The primary purpose for establishing the route was to make observations on the movements of marked birds. Similar information was recorded when the roads on the area were being traveled during the performance of other field duties. Also, farmers residing on the area cooperated by reporting observations of marked birds. A 6 X 30 binocular field glass was used to check birds for markers and bands and to observe pheasant behavior. The aluminum butt~end leg band was used as the basic criterion in determining whether a bird was marked. Additional information on pheasant movements was obtained from marked birds retrapped, lost markers found in the field, and marked birds found dead on the area. Data from the last two sources were ob tained while the investigator made a daily reconnaissance of the fields on foot during the winter and spring phases of the study. In the spring when the snow cover was disappearing, the entire area was systematically covered at least twice by the author in the search for dead birds and for markers lost from birds. The winter population for the 2,480-acre area was derived by totaling the highest roosting counts taken at the farm shelterbelts and other con centration points during the month of January. These roosting counts were taken at daybreak and as shortly thereafter as possible. The spring breeding population estimates per section were deter mined by recording the number and approximate location of all crowing cocks heard during a ten-minute period at each of five different stations. Four of these stations were located at the half-section lines and the fifth at the center of the section. While driving between the first four stations and walking to the fifth, the locations of all observed male birds were also recorded. On the basis of these data, the approximate number of males per square mile could be determined. The observed winter sex ratio was then applied to compute the total number of birds per section. A cock crowing call route (3) and a male roadside count (5) established in 1950, were run on ten mornings during the period May 5 to May 24. The information obtained was used as a check against the breeding population estimates. The observed winter sex ratio was determined by a combination of field and roadside observations (5) . WEATHER Weather data were obtained from the U. S. Weather Station at Forest City, Iowa, approximately 20 miles southeast of the area. December, 1950, was cold and dry. Temperatures were 7.3 degrees (F.) below the 44-year normal. January, 1951, had a temperature 3.9 degrees below normal, and precipitation was 0.25 inches above normal. Snowfall totaled 12.8 inches and snow depth reached a maximum of 13.0 inches. February temperatures were 0.6 degrees above normal. Snow totaling 8.5 inches fell on six days. The latter part of the month was characterized with temperatures above normal. March had the greatest snowfall, 21.0 inches, WINTER BEHAVIOR OF RING-NECKED PHEASANTS 449 with seven days having .01 inches or more of snow, and some of the most severe storms of the winter. Temperatures were 10.7 degrees below normal. Spring thaws and periodic rains left the roads impassable during the first half of April. Temperatures were 5.6 degrees below .normal and precipitation was 4.2 inches above normal. The total snowfall only amounted to 3.0 inches. COVER OF AREA There were 14 farm shelterbelts, one willow fence row, and two sloughs on the 2,480-acre area which were considered to be potential c. HERM E 181 O. IVERSON J.FURE 181 N.SIMONSON 181 0 tJ 1:81 (9) (6) CLAR. l8I (5\ WALLE(Sl SEC .15 l8I SEC -. 14 SEC . 13 CHRIS 171 WALLE E . SEIM 181 CJ, BIG ri:ll M. ASMUS (3) SLOUGH (4) l ) S .NESJE 181 "1.PIERCE 181 N SEC . 24 SEC. 23 ->- LNENo : O.OLSON T.CHRIST ~NSON 181 SHELTERBELTS NEAR BUILDINGS 181 O.B . CHRl'3TENSON 181 (2) 0 ABANDONED SHELTER BELT 181 ( )TRAPSITES (I) 1, ~SLOUGH AR EAS 0000 WILLOW FEN CE ROW - UNPICKED CORN SCALE" 0 MILES 1/2 FIG. 1. Study area. The Winnebago Pheasant Research Area, Eden Township, Winne bago County, Iowa. December 21, 1950 - May 31, 1951. winter concentration points for pheasants (Fig. 1). In general, the shelterbelts were planted about the time buildings were erected. Evi dence of some natural reproduction, especially box elder, was apparent in many of the shelterbelts. Only limited replanting has been done. Species of trees most commonly found in the shelterbelts included: box elder (Acer negundo), American elm (Ulmus americana), Chinese elm (Ulm us parvifolia), green ash (Fraxinus pennsylvanica var. lanceolata), willow (Salix spp.), plum (Prunus spp.), and eastern cottonwood (Popu lus deltoides). Pine (Pinus spp.), spruce (Picea spp.), Catalpa (Catalpa speciosa) , and maple (Acer spp.) occurred in lesser numbers. The management of these shelterbelts is, for the most part, super- 450 CAR'R'.O~l R. GIRONDAKL ficial, with occasional cuttings being made to provide firewood. The shelterbelts are used for pasturing livestock with regularity on some farms. The areas of five shelterbelts ranged from 1.2 to 4.6 acres. One of the shelterbelts on the Otto Iverson farm is referred to as "abandoned" because it is not in the vicinity of farm buildings. The willow fence row, located in section 15, is a single row of trees 30 to 40 feet tall and about 440 yards long. The row extends from the south edge of section 15 north along the half-section line. The two slough areas, both located in section 13, were 8.0 and 5.5 acres in area. These two .areas are typical of the many sloughs that were once common throughout northwest Iowa and have since been drained. Several other small depressions are found on the study area but do not have sufficient vegetative growth to be considered as potential winter cover. The eight-acre slough area, located in the southwest quarter of section 13, will be referred to as the "Big Slough." POPULATION AND SEX RATIO A January census of the 2,480-acre area revealed a total of 508 birds; the 1950 winter population figure as determined by Kozicky and Hen drickson (5) was 435 birds. The 1951 figure represented an increase of 73 wintering birds (17.0 per cent) over that for 1950 (Table 1). The high percentage of birds found in section 14 was probably influenced by two unpicked corn fields, 2 and 15 acres. During 1951, counts revealed that 322 birds, 63.0 per cent of the entire population, were wintering in section 14; during 1950, this section contained 120 birds, 27.6 per cent of the winter population. There was no unpicked corn on section 14 in 1950. The 1951 spring population was calculated to be about 60 birds per section. This figure represented an increase of approximately 16.0 per cent over the 1950 spring population figure and corresponded very closely to the increase of 17.0 per cent shown by the winter census.