Burrowing Owl Natural History Sample Clauses

Burrowing Owl Natural History. The burrowing owl is a small, ground-dwelling owl with long legs, a round head with an oval facial xxxx, and no ear tufts129. The species is semi-colonial and uses open, treeless areas for nesting. Because short vegetative structure is important in allowing for detection of predators, burrowing owls are commonly found in association with cattle, prairie dogs, and other grazers130. The species often nests in prairie dog xxxxxxx, as well as xxxxxxx dug by other animals such as badgers or foxes. Burrowing owls will use active and relatively inactive prairie dog colonies, but have been shown to experience lower rates of nest depredation and have higher rates of nesting success on larger, denser prairie dog colonies131. In northeastern Colorado, density of burrowing owls was correlated with active xxxxxx density. In 26 of 27 colonies occupied by burrowing owls, at least 50 percent of the prairie dog xxxxxxx were active132. In southeastern Colorado, burrowing owls occupied prairie dog colonies with 43 percent active burrows133. Habitat selection by burrowing owls was correlated with xxxxxx length, high xxxxxx density, low shrub cover, prairie dog activity, and closeness to water in the Thunder Basin134. Burrowing owls are opportunist feeders, consuming insects, small mammals (mice and voles), birds and other prey (Xxxx et al. 1993). Burrowing owls appear to prefer a vegetation mosaic with nesting habitat interspersed with taller vegetation for hunting135. Those burrowing owls that nest in Canada and the northern Great Plains typically leave their wintering grounds in March and April, arriving on the northern breeding grounds as late as May. Wyoming burrowing owls typically arrive on the breeding grounds in late April136. Burrowing owls begin laying eggs in late March in the southern part of the range (northern Arizona and New Mexico), and mid-May in the north (southern Canada). In the Thunder Basin, nest initiation dates are typically between April 15 and June 1137. They produce only one brood per season with 7 to 9 eggs in an average clutch and between 1.6 and 4.9 young fledged per nest attempt138. In Wyoming, an average of three young fledge 129 Xxxx et al. (1993) 130 McDonald et al. (2004) 131 Xxxxxxx et al. (2001) 132 Xxxxx et al. (2003) 133 Xxxxxxx et al. (1999) 134 Xxxxx (2005) 135 McDonald et al. (2004) 136 ibid 137 Xxxxx (2005) 138 Xxxx et al. (1993) per nest139. Northern birds leave for their wintering grounds by mid-October, while more southern birds r...