Mettke-Hofmann, C, Hamel, PB, Hofmann, G, Zenzal, TJ, Pellegrini, A, Malpass, J, Garfinkel, M, Schiff, N and Greenberg, R (2015) Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds. PLoS One, 10 (5). pp. 1-17. ISSN 1932-6203

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Abstract

Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes.

Item Type:	Article
Uncontrolled Keywords:	MD Multidisciplinary
Subjects:	Q Science > QH Natural history > QH301 Biology Q Science > QL Zoology
Divisions:	Natural Sciences & Psychology (closed 31 Aug 19)
Publisher:	Public Library of Science
Related URLs:	Author
Date Deposited:	01 Feb 2016 13:39
Last Modified:	04 Sep 2021 14:22
DOI or ID number:	10.1371/journal.pone.0123775
URI:	https://researchonline.ljmu.ac.uk/id/eprint/1118

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