"Bridget Stutchbury, author of ‘Silence of the Songbirds’ has a new book out called ‘The Bird Detective’ which is full of more amazing discoveries from her research.
Stutchbury, a recognized international bird expert was raised in Toronto, completed her MA from Queens, a Ph. D. from Yale and is now a professor of biology at York U. The particulars for her books are gathered by means of DNA testing and the use of geolocators that log the timing of sunrises and sunsets at a tagged bird’s migration location.
The female hooded warbler builds her nest and lays the eggs while the male feeds the newly hatched babies. Within eight to nine days the young leave the nest with the parents continuing to feed them for another three weeks. DNA testing of the parents and all offspring has demonstrated that not all of the babies are from this father that has been diligently feeding them and that 30% of females mate with another male. The females have been tracked visiting the nest of other nearby males that influenced them with a superior song rate per minute better than their own mate.
To summarize, the mate is acceptable for children but the guy next door that can sing better is worth a visit to increase the quality of offspring.
Did you know that purple martins only rely on human housing in eastern North America? They too have some seedy behaviour with 60% of the young females cheating with an older male, in particular one that is two to four years old. The scientific reasoning for this is easy. An older male has proven himself to be healthy and able to survive and offspring of theirs will inherit their good genes.
The blue headed vireo has tested genetically monogamous. The male builds the nest, does the majority of incubating and feeds the young which leaves him no time to attract other females. No problem here except the females practice premeditated divorce. Before the first batch of young have even left the nest, the female is off searching for another male that doesn’t have a mate. Once she locates the next male, she will have laid eggs for him to incubate within about a week.
The big question here is why wouldn’t she pair with the male feeding the babies again? Both are needed to incubate the eggs and by finding another unattached male she can have another clutch sooner.
These are only a few examples of bird acts of adultery and betrayal and you’ll have to read the book for more. Stutchbury encourages us all to become bird detectives in our backyards where we may find some surprises there too."
Pictured is a brown-headed cowbird. The females toss or eat an egg from another bird’s nest and lay one of their own in its place. The unsuspecting mother of the nest raises this baby with her own.