when do blue birds build nests

This article provides comprehensive coverage of the eggs and nests of bluebirds, encompassing various relevant aspects. It delves into detailed descriptions of egg characteristics, the timing of egg laying, the process of incubation, and more. Furthermore, the article explores bluebird nesting requirements, including nest placement, along with other important aspects of bluebirds’ nesting biology.

bluebird nest and eggsPhoto: John Brandauer /Flickr/CC by 2.0

Among folks who keep bluebird houses (nest boxes), one commonly asked question is what to do with unhatched eggs when the rest have already hatched or what to do with unattended eggs in a nest.

These questions also apply to nests outside birdhouses. Naturally, many bird enthusiasts want to help when they perceive a problem.

This article goes through some basic information about bluebird eggs and nests to help you make informed decisions.

When does egg laying begin?

The female bluebird starts to lay eggs six or seven days after the nest is finished.

Throughout the Bluebird’s range, the general timing of egg laying corresponds with the timing of nest construction. In the warmer southern states, egg-laying starts in February and March; in the colder northern states, it starts in March and April.

During April, most breeding Bluebirds are at least incubating eggs.

In what instances do eastern bluebirds abandon their eggs?

In most cases, bluebirds abandon their eggs for compelling reasons. Field observations indicate that if either the male or the female of a mated Bluebird pair dies, the pair is more likely to abandon its eggs. Extreme weather and a lack of food are additional contributing factors.

Extreme weather events and lack of food are related. In general, cold weather slows the growth of insect populations, reduces their mobility, and makes it more difficult for bluebirds to find them. As a result, bluebirds have to search for food for longer periods of time, ignoring the eggs, or even temporarily relocating to areas with food.

Repeated harassment by predators is another reason. Predators might be trying nonstop to get into the next box. Even though it doesn’t work, this kind of harassment can keep the female from laying the eggs. Since eggs and nestlings could eventually be taken by predators and relocated to another nesting site, nesting pairs might decide it is not worth their while to continue.

An additional, less common explanation is that the parents might discover after a longer than usual incubation period that the eggs are not viable. They can construct a nest on top of the eggs and begin reproducing, or they can leave the eggs and relocate to a different nest site.

Nest abandonment depends on when one of the pair is lost

During the breeding season, male and female Bluebirds have distinct roles, so the timing of one pair member’s loss can have varying effects.

Scenarios include:

  • The breeding attempt fails if the female disappears during the building of the nest, laying of the eggs, and incubation phases because the male does not perform any of these tasks.
  • Field observations suggest that the female will probably give up on the nesting attempt if the male is lost during egg laying and during the incubation period.
  • The attempt to build a nest fails if the female disappears when the brood is very young because the male does not care for the young, who will then succumb to hypothermia.
  • The female may raise the young if the male passes away when the brood is very young.
  • The surviving parent can raise the young through fledging if the male or female passes away while the chicks are still in the nest and have feathers to regulate their body temperature.

Although any of these situations could lead to a bird abandoning its nest, it is more likely that one of the birds will replace the absent one. If the young are old enough or prepared to fledge, the new replacement might assist with feeding them. On the other hand, it’s unlikely that the new replacement will be interested in eggs or very young nestlings.

FAQ

What month do Bluebirds build nests?

Year-round residents begin nest building during February and March, the same period migratory Bluebirds are just arriving in the northern states. In the states of Michigan and Minnesota, Bluebirds start building nests in March and late April.

Do Bluebirds come back to the same nest every year?

Adult Bluebirds tend to return to the same breeding territory year after year, but only a small percentage (three to five percent) of young birds return to where they hatched. Bluebirds love mealworms and can be drawn in with a small dish filled with mealworms.

When should I put out my Bluebird house?

Have your bluebird boxes in place by early spring when the bluebirds are looking for nesting sites. Boxes may also be put up later in the nesting season. In areas where bluebirds are present year round, they may use nestboxes for roosting on cold nights.

Where do Bluebirds nest in the wild?

Eastern Bluebirds put their nests in natural cavities or in nest boxes or other artificial refuges. Among available natural cavities, bluebirds typically select old woodpecker holes in dead pine or oak trees, up to 50 feet off the ground.