Tree swallow (Tachycineta bicolor) abundance, density, and nest outcomes at Red Slough Wildlife Management Area, McCurtain County, Oklahoma

Abstract

Tree Swallows (Tachycineta bicolor) expanded their range
into southern Oklahoma and northern Texas over the last 20 years. From
2009-2012, we monitored 229 Tree Swallow nests at the Red Slough
Wildlife Management Area in southeastern Oklahoma to determine
nest outcomes. Point counts were conducted to develop a population
index and density estimate for Tree Swallows at Red Slough Wildlife
Management Area. Population abundance was 3.6 Tree Swallows
detected/point and population density was 4.5 Tree Swallows/ha.
From 2009-2012, 77% of Tree Swallow nests βledged ≥1 young. Tree
Swallows had a mean clutch size of 5.2 eggs and a mean of 3.5 nestlings/
nest attempt hatched. Tree Swallows βledged a mean of 3.3 young/nest
attempt. Tree Swallow nest success varied among years, mainly due to
predation and brood reduction from unhatched eggs and early nestling
mortality. Tree Swallows in southeastern Oklahoma demonstrated nest
success rates similar to other published studies, however βledging rates
were lower than other reported estimates. We documented high rates
of successful second nest attempts at Red Slough Wildlife Management
Area compared to Tree Swallows at higher latitudes.