Henry M. Streby
David E. Andersen
Sean M. Peterson
2012
<p>Brood parasitism by Brown-headed Cowbirds (<i>Molothrus ater</i>) typically decreases the number of host juveniles that fledge: however, little information exists regarding the effect of cowbird parasitism during the post-fledging period. We monitored 115 Ovenbird (<i>Seiurus aurocapilla</i>) nests in 2006–2008 in northcentral Minnesota, six of which were parasitized. We used radiotelemetry to monitor movements of 36 Ovenbird fledglings (nine additional fledglings depredated <24 hrs after fledging were excluded from the movement analysis) from non-parasitized nests and one fledgling from a parasitized nest. Clutch sizes and productivity were lower in parasitized Ovenbird nests than non-parasitized nests, similar to populations at other locations. The fledgling we tracked from a parasitized nest (in 2008) died after 26 days. It was the only fledgling in our study that died (<i>n</i> = 20) with no sign of predation and an empty stomach. That fledgling took 12 days to travel >50 m from its nest and 25 days to travel >100 m from its nest. Fledglings from non-parasitized broods tracked for ≥25 days during 2008 (<i>n</i> = 16) took 4.1 ± 0.71 and 9.5 ± 1.14 days to travel the same distances. Our observations suggest that negative effects of brood parasitism may persist into the post-fledging period, possibly confirming observations of cowbird-only survival compiled from the literature.</p>
application/pdf
10.1676/11-050.1
en
Wilson Ornithological Society
Effects of brood parasitism by brown-headed cowbirds may persist in the post fledging period
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