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Flammulated Owl Distribution and Detections in Montana: Results from a region-wide survey

Flammulated Owl Distribution and Detections in Montana: Results from a region-wide survey. Amy Cilimburg Avian Science Center University of Montana. Landbird Monitoring Program. Bird point counts -- 1994 -– many partners Long-term monitoring and habitat relationships Management effects

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Flammulated Owl Distribution and Detections in Montana: Results from a region-wide survey

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  1. Flammulated Owl Distribution and Detections in Montana: Results from a region-wide survey Amy Cilimburg Avian Science Center University of Montana

  2. Landbird Monitoring Program • Bird point counts -- 1994 -– many partners • Long-term monitoring and habitat relationships • Management effects • Target species

  3. FLAM BACKGROUND • Neotropical migrants • Arrive MT early to mid-May • Strictly nocturnal • Not captured via other monitoring efforts

  4. FLAM BACKGROUND cont. • Feed primarily on Lepidoptera – nocturnal moths • Habitat requirements: • Large snags (Pileated WP or N. Flicker holes) • Open forests for foraging • Dense patches for roosting • Forest type • Ponderosa Pine / Douglas Fir • Open Doug fir mix

  5. US Forest Service Region 1

  6. 2005 USFS - LBMP GOALS • Develop R1 protocol for Flammulated Owl surveys • Determine distribution – especially east of the divide • Expand understanding of habitat associations – especially west • Establish repeatable routes • Determine detection probability

  7. Protocol and Planning • Protocol -- talked with owl experts and Forest Service biologists; reviewed the literature. • Combined -- understanding of owl behavior + logistical realities….. • Nocturnal Broadcast Surveys • Transects along roads or trails • Spatial data via GPS • Standardized calling procedures • Where to survey???????

  8. WHERE TO SURVEY??? • Previously established surveys on some forests, none on others • GIS MODELING • Overall, cast a wide net in “reasonable” habitat • Forest-specific vegetation and road layers • Use: age class (old growth or mature), size class, canopy cover • Stands within 500m of roads or trails

  9. Lolo National Forest

  10. STANDARDIZED DATA FORMS

  11. THE 2005 FIELD SEASON • Cold wet June • No night-time encounters with Mountain Lions, drunken locals • No one fell asleep and crashed while driving back to camp • There are owls out there!

  12. Other Owls • 49 Great Horned Owls • 24 Barred Owls • 21 Northern Saw-whet Owl • 5 Northern Pygmy Owls • 4 Boreal Owls • 3 Western Screech Owls • 2 Great Grey Owls • 2 Long-eared Owls • 1 Short-eared Owl

  13. Flam Owls detected Flams NOT detected Idaho Montana

  14. BY THE NUMBERS: • Detected 243 FLAMS – 9% of points • Set up and ran 265 transects (2721 pts) • Resampled on 5 forests – 59 transects • Approximately 206 unique owls • On all but 3 forests: Lewis & Clark, Custer, Gallatin

  15. More Numbers • Owls detected May 9-July 21 • first and last day of surveying! • Detections only slightly lower after ~ mid-June. • 65% of detections made after playing caller – early season ~50%. • Extended call increased our detections.

  16. More Results DETECTION • the probability of detecting an owl at a site in a single visit, when present. • Overall detection probability = 0.72 • OCCUPANCY • the fraction of sampling units in a landscape where a target speciesis present. • Overall Probability of Occurrence for R1 = 0.388 • 10% higher than if no detection adjustment

  17. Occupancy

  18. Occupancy, cont. HELPFUL PAPER: MacKenzie and Royle. 2005. Designing occupancy studies: general advice and allocating survey effort. Journal of Applied Ecology 42: 1105-1114. • RARE SPECIES – more efficient to survey more sampling units less intensively. • COMMON SPECIES - fewer sampling units should be surveyed more intensively.

  19. Optimal # of surveys to conduct at each site….. Table 1 from MacKenzie and Royle 2005 P = Detection probability ψ = Prob. of occurrence

  20. Occupancy, cont. • Journal of Wildlife Management 2005 • Special Section in Issue 3: The value and utility of Presence-Absence Data in Wildlife Monitoring and Research • New Book • – Occupancy Estimation and Modeling: inferring Patterns and Dynamics of Species Occurrence. 2006. MacKenzie et al.

  21. Habitat Associations • ~ 60% ponderosa pine / doug fir • ~ 75 % ponderosa + anything • ~ 25% primarily Douglas Fir with other associated species • However, need to look different scales, gis…. More work here….

  22. A FLAM was calling from the ridge in the foreground in early July.  • Primarily Doug-fir, with large P pines, and a few large snags on ridge.  • Bertie Lord Creek watershed, Sula Ranger District, Bitterroot NF. 

  23. Two Flammulated Owls called from within 50 meters of this location in mid-July. • Woods Creek watershed, West Fork Ranger District, Bitterroot NF

  24. Winter Wren

  25. http://avianscience.dbs.umt.edu

  26. FUTURE????

  27. THANKS • US Forest Service – Skip Kowalski and Forest Biologists • The many intrepid nocturnal field technicians • Vita Wright • Jim Baldwin, USFS PSW statistician • ASC Staff – Anna Noson (GIS)

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