Transcript Linking Reproductive Ecology 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
– 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
Does Habitat
Use by
Predators
Matter?
? Or ?
(Hutto 1985)
Our Basic
Approach
Interpolating Predator
Use of Study Area
Mapping
Predators
Relating Annual
Productivity or Nest
Success to
Predator Use
(Marzluff et al. 2007)
Relative Use of Area by
View1Crows
American
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Relative Use of Area by
Steller’s
Jays
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Relative Use of Area by
Douglas Squirrels
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Relative Use of Area by
Townsend’s
Chipmunks
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Relative Use by All Surveyed
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Predators
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Landscape
Correlating
Predators and
Prey at 3 Scales
Within Patch
Forest patch
Occurrence
of Corvids
0 -2 / count
1 – 1.5 / count
0.25 – 1.5 / count
Scale-specific Responses to
Crows
Bewick's
Wren
American
Robin
Dark-eyed
Junco
Blackthroated
Gray Warbler
Song
Sparrow
Pacific
Slope
Flycatcher
Swainson's
Thrush
Spotted
Towhee
Winter
Wren
Wilson's
Warbler
Scale-specific Responses to
Crows
Bewick's
Wren
American
Robin
Dark-eyed
Junco
Blackthroated
Gray Warbler
Song
Sparrow
Pacific
Slope
Flycatcher
Swainson's
Thrush
Spotted
Towhee
Winter
Wren
Wilson's
Warbler
Some species are consistently found together
Scale-specific Responses to
Crows
Bewick's
Wren
American
Robin
Dark-eyed
Junco
Blackthroated
Gray Warbler
Song
Sparrow
Pacific
Slope
Flycatcher
Swainson's
Thrush
Spotted
Towhee
Some species are consistently found apart
Winter
Wren
Wilson's
Warbler
Some
Species
Appear to
Adjust Their
Activity
Within a
Forest Patch
to the
Presence of
Nest
Predators
May adjust
most to jays
and squirrels
because they
are IN forest,
and jays are
incidental
predators and
small
mammals are
efficient,
olfactory
predators
(Vigallon and Marzluff 2005;
Bradley and Marzluff 2003)
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
Species
May Vary in
Their
Exposure to
Nest
Predators
Some Migrants live
with Few Predators
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)
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
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 (Yellowbilled 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)
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)
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.