However, many nature lovers don't realize that by allowing a birdhouse to stand unmanaged, they are indirectly harming the very birds the house was meant to benefit, by providing a breeding ground for the worst enemy of bluebirds - the House Sparrow. If you have a birdhouse in your yard, your good intentions in attempting to provide birds with a place to nest should be applauded. Please Help Bluebirds and Other Native Birds Survive and Thrive: There is also a letter you can use for commercial establishments allowing HOSP to breed/roost/feed. Because chick-feeding by males is tied to opportunity for paternity, influences success in the current nest, and does not affect the male's future breeding success, it appears to be parental rather than mating effort.Handout on Neglected Nestboxes Bluebird and Small Cavity Nester Conservationĭownload MS Word document you can customize, or you can use this for talking points. These experiments suggest that male parental care increases nesting success in western bluebirds and that replacement males use an all-or-none rule to determine whether or not to feed chicks: if they are present during the fertile period they feed at typical rates if they are not, they usually do not feed at all. We found no future benefits of provisioning by replacement males those that fed were no more likely to breed with the female on her subsequent attempt than were males that did not feed, and subsequent clutch sizes were not reduced for females rearing young without the male's help.
Female condition was not affected by male provisioning and unassisted females were as likely to survive to the next breeding season as assisted females. Older females were better able to raise young without the male's help than were yearling females. Field metabolic rates of unassisted females were 17% higher than those of control females, but the difference was not statistically significant. Unlike assisted females, unassisted females exhibited reduced nesting success and their 14-day-old chicks weighed less than controls. Females without a feeding replacement male compensated by feeding more themselves so that overall feeding rates were not compromised, but they reduced their brooding time.
Feeding replacement males and the females they joined fed at rates similar to controls. Replacement males were not infanticidal and 7 (47%) fed nestlings.
We removed resident males of socially monogamous pairs during laying and after clutch completion to examine chick-feeding rules used by replacement males and current and future fitness consequences of paternal care. In western bluebirds ( Sialia mexicana), most pairs remain together for life and share equally in post-hatching parental care.
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