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Linking Reproductive Ecology and Habitat Use to Conservation

Linking Reproductive Ecology and Habitat Use to Conservation. Dead Trees are Important. (Martin et al. 2004). Nest Predation is an Important Selective Force on Birds. Higher in tropics and on open nesting birds

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Linking Reproductive Ecology and Habitat Use to Conservation

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  1. Linking Reproductive Ecology and Habitat Use to Conservation

  2. Dead Trees are Important (Martin et al. 2004)

  3. Nest Predation is an Important Selective Force on Birds • Higher in tropics and on open nesting birds • Parental behavior may be adjusted to reduce conspicuousness, guard nest, or thwart predators • Introduction of exotic predators is devastating • Tipping the balance in favor of certain native predators may be devastating • Increased edges and removal of top carnivores often leads to increases in generalist, mesopredators • LOVE YOUR LOCAL COYOTE

  4. Does Habitat Use by Predators Matter? ? Or ? (Hutto 1985)

  5. Our Basic Approach Interpolating Predator Use of Study Area Mapping Predators Relating Annual Productivity or Nest Success to Predator Use (Marzluff et al. 2007)

  6. Relative Use of Area by American Crows

  7. Relative Use of Area by Steller’s Jays

  8. Relative Use of Area by Douglas Squirrels

  9. Relative Use of Area by Townsend’s Chipmunks

  10. Relative Use by All Surveyed Predators

  11. Landscape Correlating Predators and Prey at 3 Scales Within Patch Occurrence of Corvids 0 -2 / count Forest patch 1 – 1.5 / count 0.25 – 1.5 / count

  12. Scale-specific Responses to Crows Pearson Correlation Coefficient (r)

  13. Scale-specific Responses to Crows Pearson Correlation Coefficient (r) Some species are consistently found together

  14. Scale-specific Responses to Crows Pearson Correlation Coefficient (r) Some species are consistently found apart

  15. Some Species Appear to Adjust Their Activity Within a Forest Patch to the Presence of Nest Predators

  16. May adjust most to jays and squirrels because they are IN forest, and jays are incidental predatorsand small mammals are efficient, olfactory predators(Vigallon and Marzluff 2005; Bradley and Marzluff 2003)

  17. Species May Vary in Their Exposure to Nest Predators Bewick’s Wrens, Dark-eyed Juncos, and Spotted Towhees exist with abundant predators --all permanent residents

  18. Species May Vary in Their Exposure to Nest Predators Some Migrants live with Few Predators

  19. Landscape Scale:Few Consequences of Living with Predators Correlations between total predator counts or counts of only corvids (subdivided and done various ways) were weak highest r = -0.19 lowest p = 0.19 (1-tailed)

  20. Conclusions • Some songbirds may avoid nest predators within forest patches • At least we detect them less frequently during point counts in areas used heavily by predators • Not avoidance during count (abundances during a count were often positively correlated), but avoidance of areas we determined independently to be used most frequently by predators • Avoidance of jays and sciurids was stronger than avoidance of crows • Living with jays and sciurids can reduce productivity which may reinforce the avoidance behavior we documented

  21. Breeding May Occur When and Where We Don’t Expect It Hydrogen Isotopes Five neotropical migrants appear to breed in Western Mexico AFTER also breeding in more northern range (Yellow-billed Cuckoo, Cassin’s Vireo, Yellow-breasted Chat, Hooded Oriole, Orchard Oriole) Coastal Sinoloa and Baja get late summer/autumn rains that make it important areas for breeding that are in need of conservation (Rohwer et al. 2009)

  22. Sibling Rivalry, Renesting and Captive Propagation • Often the number of young that hatch is greater than the number that fledge • Cross foster or captive raise “extras” • When a bird’s nest fails, they typically renest • Take eggs and double clutch to increase population (Cade and Jones 1993)

  23. Literature • Cade, T. J. and C. G. Jones. 1993. Progress in restoration of the Mauritius Kestrel. Conservation Biology 7:169-175. • Hutto, R. L. 1985. Habitat selection by nonbreeding, migratory land birds. Pp. 455-476 in. M.L. Cody (ed.). Habitat Selection in Birds. Academic Press, San Diego. • Martin, K., K. E. H. Aitken, and K. L .Wiebe. 2004. Nest sites and nest webs for cavity-nesting communities in interior British Columbia, Canada: nest characteristics and niche partitioning. Condor 106:5-19. • Marzluff, J. M., Withey, J. C., Whittaker, K. A., Oleyar, M. D., Unfried, T. M., Rullman, S. and J. DeLap. 2007. Consequences of habitat utilization by nest predators and breeding songbirds across multiple scales in an urbanizing landscape. Condor 109:516-534. • Rohwer, S., K. A. Hobson, and V. G. Rohwer. 2009. Migratory double breeding in Neotropical migrant birds. Proc. Natl. Acad. Sci. 106:19050-19055.

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