Removal of old nest material decreases reuse of artificial burrows by burrowing owls

Abstract

Artificial burrows are considered an important management and conservation tool for burrowing owls (Athene cunicularia). This species regularly adorns natural and artificial burrows with mammal dung and other materials, which remain between years so that previous use of a nest site is often obvious. Moreover, ectoparasites (fleas) potentially overwinter in accumulated material and infest subsequent occupants. How evidence of prior use affects burrowing owl nest‐site decisions is not completely understood. We examined potential effects of the presence of old nest material on reuse of nests by burrowing owls in southwestern Idaho, USA, during 2004 and 2005. We manipulated artificial burrows that owls used for nesting in the prior year by; 1) removing material from the entrance, tunnel, and nesting chamber and replacing it with fresh soil; 2) microwaving old nest material to kill ectoparasites before returning it; or 3) removing and returning material without treatment to serve as a control. Relative to removal burrows, odds of burrowing owl reuse of ‘control’ and “microwave” burrows were 3.5 and 3.8 times greater, respectively. Removing ectoparasites by microwaving did not increase odds of reuse relative to control burrows, and fleas were present on nestlings in all 3 treatment groups. Presence of old material may help owls locate specific burrows when returning from migration or may provide physiological and feeding benefits. Thus, cleaning by removal of nest material from previously used artificial burrows may be counterproductive if maximizing reuse of nest sites by burrowing owls is a management objective. © 2015 The Wildlife Society.

Nest-Site Selection In A High-Density Colony of Burrowing Owls

“…Nest-site reuse was low through the study, with only 12% used all 6 yr. However, we found betweenyear nest-site reuse (46%) was within the range reported elsewhere: 12% (Griebel 2000), 43% (Riding and Belthoff 2015), ,50% (Rich 1984), 55% (Rodriguez-Estrella 1997), 60% (Mealy 1997), and 87% (Holmes et al 2003). Our low nest-site reuse over 6 yr, combined with consistently high occupied nest densities, indicates sufficient candidate nest sites were available to Burrowing Owls within our study area, and our higher between-year reuse hints at social factors such as nest-site fidelity.…”

“…There might be some advantage to reusing nest burrows, as Mealy (1997) reported 53% of pairs reusing burrows fledged !1 young, whereas only 19% of pairs using new burrows fledged !1 young. Riding and Belthoff (2015) reported that 87% of reused artificial nest sites had fledged !1 young the year previously, whereas 59% of artificial nest sites not reused had fledged !1 young the year previously. The advantages of reusing nest sites over the short term might be offset by Figure 4.…”

Artificial Burrow Use By Burrowing Owls In Northern California

“…In addition, Burrowing Owls raised in artificial burrows at SJC nested in artificial burrows more frequently than in natural burrows. Riding and Belthoff (2015) report that at their study site in southwestern Idaho, Burrowing Owls rarely used natural burrows for nesting in areas where artificial burrows were present, possibly because of a shortage of suitable natural burrows. At SJC, however, natural burrows were abundant and seemingly not a limiting factor, suggesting that owls preferred artificial burrows.…”

Detecting Burrowing Owl Bloodmeals inPulex irritans(Siphonaptera: Pulicidae)

“…The few available studies of fleas on burrowing owls indicate that 1) Juveniles infested with fleas disperse from natal areas significantly later than those treated with insecticide, but only in some years (V. Garcia and C. Conway, unpublished data), 2) Nests with higher flea loads have lower productivity (J. Welty and J.R.B., unpublished data), and 3) Nest-site reuse does not appear to be affected by the presence or absence of fleas (Riding and Belthoff 2015). Other important aspects of the host–parasite relationship between burrowing owls and P. irritans are poorly understood, e.g., if and how this relationship alters owl physiology, immunology, parental care, or juvenile survival after leaving nests, and if it has any long-term reproductive consequences for the owls (e.g., Richner and Tripet 1999).…”