Northern Prairie Wildlife Research Center
Simply putting out bluebird boxes without checking progress throughout the nesting season can be doing more harm than good for bluebird populations. One of the most important reasons for monitoring is to prevent house sparrows from using the nest boxes. Monitoring also allows you to keep track of nesting results which are important for contribution to the local wildlife agency.
Begin checking bluebird boxes in mid-March and continue checking each box weekly. If you cannot find the time weekly, insure you check them at least once a month. The note card shown below is a good guideline and can be duplicated to provide one for each nest box.
Record your results of monitoring as you move around the trail, keeping the cards for reporting overall information at the end of the nesting season. Approach nest boxes and gently tap on the outside of the box. Many times the bird will fly off as you approach or when the box is disturbed. This is normal and the bird will return after you have checked the nest.
Females may also sit quietly on the nest as the door is opened. In this case, close the door and return later. Bluebirds are very tolerable of humans. All birds have a poorly developed sense of smell and touching around the box, eggs or birds will not cause the bird to abandon the nest. All of this is part of the enjoyment and learning associated with a bluebird trail.
|Monitoring nest boxes and observing eggs and birds as they develop is one of the joys of having a bluebird trail. A bird's sense of smell is poor; therefore human scent will not affect an adult bird's return to the nest. Here, an individual removes an old nest after young birds have fledged.|
There is one time that nest boxes should not be opened. This is the time period about ten to twelve days after the eggs have hatched. Young birds will have partially developed flight feathers at this time and opening the box may cause them to prematurely flutter to the ground and become food for predators.
If you are not quite sure of the exact age of the birds, it is best to play it safe and observe from a distance or open the door only a crack to peer in. Some folks have even gone as far as using a small dental instrument mirror to view inside the next box without ever opening the door.
On the fifteenth day after egg hatching, the birds should have fledged and the nest should be removed. Take the old nest out, as well as any dead birds, and move the material away from the area as this can attract predators.
Remove all house sparrow nests immediately. Be sure that any of these nests are, in fact, house sparrow nests by referring to the information presented in the section on Other Songbirds Utilizing Bluebird Trails. House sparrows and starlings are not protected by law and should be disposed of. All other songbirds are protected and it is illegal to tamper with or harm their nests in any way.
After the nesting season is over, clean out the boxes and then recheck again in the following spring. Some people simply leave the doors open on the boxes to prevent small mammals from using them as nesting areas.