| Popis: |
We measured reproductive success of 52 Chihuahuan raven (Corvus cryptoleucus) nests in the southern High Plains of Texas in 1999. Egg laying was initiated between 12 April and 21 June. We observed 5.2 ± 0.2 eggs (mean ± SE) per nest, 3.3 ± 0.3 hatched chicks per nest, and 2.6 ± 0.2 fledged chicks per nest. Incorporating “days at risk,” we estimated reproductive success was 36.5 ± 0.5%, and reproductive output was 1.9 fledged chicks per nesting female. Average distance from each nest to its nearest neighbor nest was 851 ± 168 m (minimum = 233 m, maximum = 8,465 m). Nest success was unrelated to nearest neighbor distance or nest height, but was correlated with clutch initiation date. The likelihood of nest failure increased by 0.9% with each passing day. |
