Raptor and Corvid Use of Utility Poles: An Assessment of the Efficacy of Perch Deterrents Presented by: Phoebe R. Prather Advisor: Dr. Terry A. Messmer Jack H. Berryman Institute Utah State University

Previous Research • Man-made vertical structures are believed to lead to increased: • Raptor and corvid visitation.

• Access to habitats.

• Availability of perch, nesting, and roosting sites.

• Foraging and predation efficiency.

Fragmentation • Divides suitable habitat. • Increases isolation of populations.

• Abandonment of sites.

Management Need • Evaluation of effects of human infrastructure such as power lines on population.

Conservation Strategy • Retrofitting structures with perch discouragers to deter raptors and corvids from perching.

Study Objective • Test the efficacy of five types of perch discouragers on reducing the number of perching events of raptors and corvids.

Study Site • Gunnison Sage grouse Conservation Study Area, San Juan County, Utah.

Study Site

Discouragers One Fire Fly Two Fire Flies

Discouragers Cones (Kaddas) Triangles

Discouragers Spikes (Mini-zena) No treatment

Study (2007-2008) • 7.5 miles of power line with 84 poles.

Methods • Divided into 14 blocks of 6 poles. – Each block contained one of each discourager and a control.

– Treatments and control were randomly assigned.

Methods - Surveys • Began mid-January, finish end of April.

• Surveyed twice a day, five days a week.

• Entire line walked once a week.

– Evidence of depredation events and electrocutions.

Methods - Survey Protocol • Starting point (east or west) randomly selected.

• Alternate routes taken to starting point.

• Five minutes spent at starting point and each mile point.

Methods - Survey Protocol • Observations: – Species and numbers of individuals within a quarter mile of either side of the powerline.

• Flying, on ground, perched on trees, fences or poles of a different line.

– Species and numbers of individuals perched on the study poles.

• Individual counted more than once if continued down the line perching on different poles.

Methods – Exact positions of birds on study poles.

Results • No signs of electrocutions.

• One dead grouse on the road.

• Observations of grouse near road.

2007 Golden Eagle Common Raven Red-tailed Hawk Rough-legged Hawk Northern Harrier Unknown Ferruginous Hawk Results 278 39 35 15 8 2 1 2008 Golden Eagle Common Raven Rough-legged Hawk Ferruginous Hawk Bald Eagle Unknown 230 23 9 3 2 1

2007 Results

Golden Eagles

70 60 50 40 30 20 10 0

1FF control triangles Treatment cones spikes 2FF

GOLDEN EAGLE Cross Arm 45 40 35 30 25 20 15 10 5 0 control spikes cones triangles Treatments 1FF Insulator Cover 45 40 35 30 25 20 15 10 5 0 control spikes cones triangles Treatments 1FF 2FF 2FF

2007 Results •

Total:

•

278 perching events.

•

Cross Arm: 122

•

Insulator Cover: 156

2008 Results

Golden Eagles

40 30 20 10 0 90 80 70 60 50

1FF 2FF control Treatment cones spikes triangles

GOLDEN EAGLE Cross Arm 70 60 50 40 30 20 10 0 control spikes cones triangles Treatment 1FF 2FF Insulator Cover 70 60 50 40 30 20 10 0 control spikes cones triangles Treatments 1FF 2FF

2008 Results

Total: 231 perching events.

Cross Arm: 112 Insulator Cover: 119

Results

Discussion- Problems

Discussion- Problems

Discussion

Discussion

Conclusions

Acknowledgments • Advisor: Dr. Terry Messmer • Funding: – PacifiCorp – Avian Power Line Interaction Committee.

– Bureau of Land Management • Field Technician Erin Colin.

Questions?