Promiscuity in other bird species (like Saltmarsh Sparrows) may be because they are at high risk of nesting losses, which might encourage them to seek other or multiple partners in a desperate scramble to reproduce. It may also be more common with younger males and older females. Nesting occurs from March through August. The Audubon Society’s Christmas Bird Counts from 1980 to 2004 also show a three-fold increase in population. Instead, each feather barb has a thin layer of cells that absorb all wavelengths of color except blue. However, backyard bluebirders have anecdotally reported multiple failed nesting attempts that appear to have involved the same pair, where the eggs were infertile and did not hatch despite repeated attempts. On rare occasions, and perhaps due to the lack of nesting cavities, two females and a … Occasionally (maybe in 1% of nests in EABLs (Gowaty and Bridges), 6% of nests in one study of WEBLS (Dickinson and Akre 1998) a female without a nest (e.g. The male continues to take care of the recently fledged young while the female begins to re-nest. It is likely that up to 70% of all Bluebirds die before reaching their first birthday. Bluebirds do form pair-bonds during the breeding season. Another WEBL study in Montana found 13% of nestlings in 27% of nests were extra-pair (Duckworth 2006a) Gowaty found that as many as 20% of EABL(?) broken links/have suggestions/corrections, please contact me! Bluebirds have no blue pigments in their feathers. Feel free to link to it (preferred as I update content regularly), or use text from it for personal or educational © 2020 Wild Birds Unlimited, Inc. All Rights Reserved. It was long thought that bluebirds were monogamous, with mated pairs staying together for life. Bluebirds raise their young in old or pre-existing nesting cavities and have a nesting success rate of about 60%. Eastern Bluebird hunts from a perch, diving down on ground to catch a prey. Can more than one female tend a nest? Western bluebirds are monogamous, with males and females forming long-term bonds, though they are not always faithful. Bluebirds love mealworms and can be drawn in with a small dish filled with mealworms. Sometimes, young bluebirds from one brood will stay near the nest to help their parents raise a second brood. are copyrighted, and may not be used without the express permission of the photographer. 10% (2 out of 20) females that tried to renest in a single year apparently switched mates between broods (JAB and PAG, BNA), Pairs are considered "bonded" when the females enters a cavity with a male for the first time (Krieg 1971). This is equivalent to a two hundred pound human eating 24 pounds of food each day. When choosing natural nesting cavities, studies have shown that Eastern Bluebirds select abandoned woodpecker nests at least 75% of the time. See disclaimer, Predators are less likely to find a new nesting cavity than one that has been in existence for a few years. Eastern Bluebird is monogamous, and pair stay together during whole season, and may breed together for more than one season. See more on helping, along with a video. However, some birds may switch mates during a breeding season to raise a second brood. Occasionally, one male will mate with two females. Pairs are more likely to stick together if a previous nesting was successful. In a Montana study, 13% of nestlings were extra-apir (Duckworth 2006a.) This is an optical illusion known as structural color: the iridescent blue effect is produced by mostly colorless feathers in layers that interact with light waves, bouncing back only blue wavelengths of light toward our eyes. Eastern Bluebirds (EABL) usually pair up in late fall or winter time. DNA studies show that an average of one in five eggs in the nest is the result of a quickie … One study of Eastern Bluebirds (EABL) in Georgia and South Carolina indicated that about 95% of the time, nestings involve one male and one female. Please honor their copyright protection. They are generally "socially monogamous," meaning that a single male and female form a basic social unit in breeding territory.