Distribution, habitat, and management of ferruginous pygmy-owls in the Altar Valley and beyond
Aaron D. Flesch
School of Renewable Natural Resources
University of Arizona Overview
• Determine • distribution • abundance • important habitat elements
• Discuss influence of land-use
• Consider implications for management and recovery
• Questions Data
Altar Valley – 1999
• Surveys and habitat research
Sonora, Mexico – 2000-’03
• Quantified distribution, abundance, and habitat Altar Valley - Study Area
Excluded • North of MP 31 • Los Encinos •Elkhorn Design – Altar Valley
• Surveyed best areas
• Size estimates of 4 home ranges
• Habitat selection within 3 home ranges Sonora -
Study Area Arizona
Excluded • Above 1,200 m • Gran Desierto de Altar • Chihuahuan desert • Urban centers 100 km • Agricultural areas
Sinaloa Design - Sonora
Stratified Random Sample Two Strata:
• Major Vegetation Community
• Topographic Formation Vegetation Communities
Arizona Upland Lower Colorado River Valley Central Gulf Coast Plains of Sonora Semidesert Grassland Sinaloan Thornscrub Sinaloan Deciduous Forest Topographic Formations & Site Selection
Canyons Lower Upper Valley Bajadas Bottoms Bajadas Owl Surveys - Sonora and Altar Valley
Tape Playback Surveys
• Conspecific territorial calls • 8 min – Sonora • 10 min – Altar Valley
Nest Searches Sonora - Explanatory Variables
Physiography • Slope • Drainage width and density
Vegetation • Formation type and riparian width • Canopy height and vegetation volume • Species composition Cavity Substrates • Abundance of large cacti and trees Land Use • Intensity of grazing, woodcutting, and agriculture ooa-Frequency ofOccurrence Sonora - % Frequency 100
AZ Uplan 20 40 60 80 0 C o lorado Val d (69)
ley (20 Gulf
Coast (21))
Pla i Grasslanns (65)
Thor d (56) n scru D e b cid. (140) F orest
(21)
So n ora (392) Relative AbundanceVariedwithLatitude F 376
= 21.50, No. males/station 0.0 0.5 1.0 P <0.0001 ot North South DistributionDistribution && abundanceabundance ofof ferruginousferruginous pygmy-owlspygmy-owls in in Sonora, Sonora, Mex. Mx. 2000-01.2000-01.
Sonora - Important Factors
PP=<0.0001 0.0075 P = 0.0003 40 OddsOdds == 1.91.02 40 Odds = 3.4
30 30
20 20
10 10 % Stations occupied 0 0 0 1030507090 0 1030507090 Riparian woodland (%) Riparian mesquite (%) Sonora - Important Factors: Riparian Vegetation
0.6
0.4
No. males/station 0.2
0 200 400 600 800 Width of riparian vegetation (m) Sonora - Important Factors: Vegetation Volume
Semidesert Sinaloan 0.6 Grassland Thornscrub
0.4 No. males/station 0.2
10 20 30 40 50 23 29 35 41 47 53 Riparian volume 1-3 m (%) Upland volume 1-3 m (%) Sonora - Important Factors: Cavity Substrates
Substrate 40 Absent Present 30
20
10 % Stations occupied
0 Cacti: P <0.0001 Odds = 21.5 cacti trees Trees: P <0.0001 Odds = 1.9 Sonora - Large Cacti: One vs. Many
30
20
10 % Stations occupied % Stations 0 0255075100 % Quarters present Sonoran Desert: Upland Vegetation
Mesquite Ironwood Paloverde 50 40 30 20 10
% Stations occupied occupied Stations % 0 0 10305070 0103050 0 10305070 Dominance in uplands (%) Land Use: Woodcutting
40
30
20
10 % Stations occupied % Stations 0 None Low Mod. High
Woodcutting intensity Land Use:GrazingI
% Transects occupied 10 30 50 70 Statewide o o.High Mod. Low Grazing Intensity Odds = 0.21 P = 0.018 Land Use: Grazing II
Valley Bottoms Upper Bajadas Low 60 Moderate 0.7 High
40 0.5
20 0.3 No. males/station % Transects occupied % Transects
0 0.1 <350 >700 Low Mod. High Elevation (m) Grazing Intensity Land Use: Grazing III
Semidesert Grasslands
30 Grazing intensity Low Moderate 20 High
10 % Stations occupied
0 Upper Lower Valley Bajada Bajada Bottom Land Use: Agriculture
Statewide Valley bottoms 0.5
0.3 No. males/station 0.1 01020 Agriculture dominance (%) Altar Valley
• 2 small areas occupied by numerous individuals
• 5 areas occupied by pairs Altar Valley – Habitat Use
• Habitat • Mesquite woodlands with ≥1 saguaro • Riparian woodlands with large broadleaf trees
• Habitat selection within home ranges •Select • woodlands with adjacent desertscrub • larger, taller trees Altar Valley – Spatial Use
• Spatial Use • 4 home ranges 9.9 to 47.3 ha Conclusions
• Well distributed throughout Sonora
• Rare in Altar Valley
• Habitat limitations? N. Smith
• Importance of Altar Valley to recovery?
• Is recovery compatible with existing land uses? Connections with Arizona
Tohono O’odham Nation
Occupied site Limiting Factors and Management
• Altar Valley: Cavities
• Promote substrate regeneration
• Limit threats in areas suitable for saguaros •Fire • High grazing intensity Augmentation in the Altar Valley
• Add Cavities
• Nest Boxes • Saguaro Translocation
Sasabe
G. Proudfoot Management in Altar Valley
Conflicts or compatibility
Use and Management • Livestock grazing • Woodcutting • Prescribed fire
Pygmy-owl Habitat • Cavities • Woodlands Management in Altar Valley II Acknowledgements
U.S. Fish and Wildlife Service: Frank Baucom, Charles Sanchez, and Wayne Shifflett, AZESFO, Region II, BANWR
Mexico Coordinator: Eduardo Lopez Saavedra, IMADES
Field Assistants: Gabriel Valencia Ortega, Elliott Swarthout, Shawn Lowrey, Greg Greene, Sky Jacobs, Rob Hunt, Andres Villarreal, Alexis Bachrach
My Advisor: Bob Steidl
Special Thanks: People and Landowners of Sonora and the Altar Valley, Arizona