Do bluebirds abandon their eggs? The short answer is yes. This might be one of the most disheartening experiences many birders have. You’re probably looking for a reasonable explanation why this happens.
So, why do bluebirds abandon their eggs? The main reason is one or both bluebird parents could be scared or killed by a predator or humans. Bluebirds also abandon their eggs due to poor incubation, insect infestation, overheating, and poor weather.
Apart from that, there are some other reasons out there.
Bluebirds may abandon their eggs for many reasons. Here we’re going to talk about the 7 most probable reasons.
Just like humans, bluebirds can be infertile. For your information, infertility in birds is a birding pair is unable to produce eggs with viable embryos. Typically, an infertile bluebird pair can mate, lay, and incubate eggs.
Once the bluebird parents realize they’re not going to get chicks, they’ll either abandon the eggs or throw them out of the nest. Eventually, they start building a new nest, even right atop the unfertilized eggs.
If one or both bluebird parents pass away, the eggs could be abandoned. Something unfortunate may even happen to them due to the attacks of natural predators, such as cats, snakes, raccoons, foxes, and larger birds like hawks.
If one parent passes away or is killed by a predator, the other one, especially the female usually takes the responsibility because the male cannot incubate eggs. However, the female may abandon the eggs and look for a new partner.
Bluebirds may abandon their eggs because of poor incubation. The female might be inexperienced. She might leave the eggs too many times while incubating. As a result, the embryos inside the eggs won’t develop enough.
There are several reasons why the female leaves the eggs while incubating.
Bluebirds might abandon their eggs if any of their predators, such as cats, snakes, and raccoons and some other birds like house sparrows and house wrens destroy some or all of the eggs.
Compared to other predators, snakes and raccoons devour bluebird eggs more. House sparrows and house wrens don’t usually devour but destroy the eggs.
While incubating eggs, bluebird parents have to leave the nest after a certain period to eat food. They could be off the nest for up to half an hour (30 minutes). However, the female hardly gets up off the eggs during incubation.
If you look inside the nest while the parents are absent, you might assume that the eggs are abandoned. Maybe, the parents haven’t started hatching the eggs yet. It’s also possible that they’re monitoring the eggs from the distance.
Bluebirds aren’t usually scared of their competing birds, predators, or humans. Once they get scared, they will return to the nest. But, if they feel excessively harassed or disturbed, they might give up the nest and abandon the eggs.
Competing birds such as house sparrows and house wrens try to destroy bluebirds’ eggs. On the other hand, animal predators, like snakes and raccoons usually raid the nest. Humans become too close to the nest.
If a bluebird nest becomes infested with a lot of insects, such as mites, ants, and flies, this might be unbearable for the bluebird parents.
Sometimes, the parent birds think that it’s not worth investing the energy on a specific egg. The insects would reduce the chances of the egg’s survival after being hatched. Therefore, the parents abandon the egg.
Now that you know why bluebirds abandon their eggs, you should help them to incubate their eggs without any hassle. Although we cannot stop this from happening, we can try to monitor the nest box properly.
However, we hope you have learned a lot about the reasons bluebirds may abandon their eggs. Have you ever found an abandoned bluebird egg? Share your experience with us below in the comment section.
