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short research
contribution |
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The painted redstart (Myioborus pictus L.) search rate of a
cryptic versus conspicuous prey: a
field test of optimal search models |
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Piotr G. JABŁOŃSKI
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Centre
for Ecological Research, Polish Academy of Sciences, 05-092 Łomianki,
Dziekanów Leśny, Poland, and University of Arizona, ARLDN, 611 Gould Simpson,
Tucson, AZ 85721, USA, e-mail: piotrjab1@wp.pl
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Abstract:
Models of optimal search rates predict that predators increase
the search rate when availability of conspicuous prey increases relative to
cryptic prey. I tested this prediction by comparing foraging hop rates by 19
Painted Redstarts (Myioborus pictus)
– insectivorous birds in Arizona, USA. Redstarts often use flashy displays of
open wings and tail to flush their prey and to subsequently chase the prey in
air. Such flush-displays make the prey conspicuous and easy to detect. Hence,
foraging mode affects relative availability of conspicuous versus cryptic prey: birds foraging
with frequent flush-displays encounter conspicuous prey more often then birds
foraging with infrequent flush-displays. As predicted, the hop rates during
foraging with infrequent flush-displays were lower than hop rates during
foraging with frequent displays. |
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Key words: search rates, foraging, flush-pursue, Myioborus pictus |