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1 September 2012 Temporal and Spatial Patterns in Abundance of the Wedge-Billed Woodcreeper (Glyphorynchus spirurus) in Lowland Ecuador
John G. Blake, Bette A. Loiselle
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Glyphorynchus spirurus (Wedge-billed Woodcreeper) is one of the most common birds in the understory of many tropical forests of Central and South America but few studies have focused on its abundance and distribution. We use data from mist nets and direct observations over a 10-year period to examine patterns of abundance and distribution on two 100-ha plots (Harpia, Puma), ∼1.7 km apart in lowland forest of eastern Ecuador. Birds were captured in mist nets (96 nets/plot) that were open for ∼6 hrs/day for 1 day each in January and February; direct observations were made along transects within each plot during February (7 yrs) and April (4 yrs). We recorded 861 captures (447 recaptures) on Harpia and 963 captures (540 recaptures) on Puma; capture rates (birds/100 mist-net hrs) were slightly higher on Puma, largely a result of the greater numbers of recaptures. Number of individuals captured per year did not differ between plots. Mean (± SE) recapture distance within a year was less on Harpia (94.5 ± 6.1 m) than on Puma (121.6 ± 7.3 m) but recapture distances between years did not differ between plots (108 and 97 m, respectively for Harpia and Puma). Number of captures had a clumped distribution with some nets capturing many more individuals than others; number of captures per net was not correlated with captures at nearby nets. We recorded 490 Glyphorynchus during observations on Harpia (Feb samples) and 384 on Puma. Number of observations was greater on Harpia during 6 of 7 years. Numbers of observations had clumped distribution patterns on both plots; significant autocorrelations likely reflected the difficulty of detecting individuals by voice when >50 m from a transect. Comparisons with published data from other sites in Central and South America indicate considerable spatial variation in abundance but reasons for geographic variation in abundance need further investigation.

John G. Blake and Bette A. Loiselle "Temporal and Spatial Patterns in Abundance of the Wedge-Billed Woodcreeper (Glyphorynchus spirurus) in Lowland Ecuador," The Wilson Journal of Ornithology 124(3), 436-445, (1 September 2012).
Received: 5 February 2012; Accepted: 1 May 2012; Published: 1 September 2012

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