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41.
Angelika Poesel Douglas A. Nelson H. Lisle Gibbs John W. Olesik 《Behavioral ecology and sociobiology》2008,63(1):153-158
Tracking dispersal and migratory movements of animals over small and large spatial scales is a challenge. In birds, a promising
yet underutilized tool is the trace elemental composition of feathers. The elemental profile of a feather may reveal information
about the geographic origin of a bird provided that molting occurs on the breeding grounds and that elemental differences
exist between breeding areas. Here, we explore the use of trace elemental composition in body feathers of the Puget Sound
white-crowned sparrow Zonotrichia leucophrys pugetensis as a tool (1) to discriminate among birds collected in four different song dialect populations along a 400-km stretch of
the Pacific Northwest coast and (2) to assign males singing nonlocal dialects in one population to potential natal populations.
Inductively coupled plasma mass spectrometry detected 34 trace elements in sampled feathers and in a discriminant function
analysis seven of these elements differed among the four source populations. Half of the six nonlocal dialect singers, who
were likely to have immigrated into the focal population, were assigned to a population that matched their song dialect. Our
study suggests that feather microchemistry is a promising tool for identifying geographic origins of dispersing birds over
small geographic scales and in combination with other markers, such as song, may give insight into ecological and evolutionary
processes. 相似文献
42.
A wide variety of hypotheses has been proposed to explain the structural diversity in bird song repertoires. Song diversity
is frequently described in terms of song “types” or within-type “variants.” Male Puget Sound white-crowned sparrows, Zonotrichia leucophrys pugetensis, produce variants of their single adult song type by altering the number of repetitions of syllables in the terminal trill.
We tested whether variation in trill length correlated with distance to the receiver and with signaling context as predicted
by the eavesdropping avoidance hypothesis and the strategic signaling hypothesis. In accordance with the eavesdropping avoidance
hypothesis, males sang variants with shorter trills, and sang quieter and less frequently when near their mate during the
incubation phase than during spontaneous singing while unpaired. Males also sang variants with short trills, but at a high
rate and variable amplitude when within 10 m of an opponent during close male–male territorial interactions. In agreement
with the strategic signaling hypothesis, males decreased trill length immediately before chasing an opponent, but did not
change length consistently prior to flight. We conclude that the occurrence of short quiet songs sung near the mate agrees
with predictions of the eavesdropping avoidance hypothesis, while short songs sung near other males are best explained by
the strategic signaling hypothesis. Trill length variation may be a conventional signal of aggressive intentions in male–male
contests stabilized by receiver-imposed retaliation costs. 相似文献