Nest Building
This past two weeks we have been seeing a lot of nest boxes being visited by the males and in some cases by both the male and female bluebirds as a pair.
Although the male bluebird may take the lead in exploring nest boxes and trying to draw the female to certain sites, it is the female who makes the final choice of where the nest is built. This choosing can be done in a day, or it may take weeks. Again, pairs that have bred in the area before are usually faster at selecting a site; inexperienced pairs are often slower.
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A couple checking out #18
Thanks Nancy for this photo!
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The female is also the one that does all of the actual nest building. Males may carry nesting material during courtship, and a little later they may carry bits of it again, possibly to stimulate the female, but this never amounts to much real building. While the female is building, the male may even enter the nest and remove a stray bit of material. Why he does this is not known.
A nest can be completed in just 2 days but on average it takes 4-5 days. In some cases, especially early in the season, nest building may start and stop over a 6-week period. Thus, when you see nest building, do not be surprised if the birds leave and then come back, if they start to build a little in several boxes, or if they take a particularly long time. All of these patterns and more are just part of the tremendous variation in individual bluebird habits.
Bluebird nests are constructed of grasses, pine needles, fine weed stalks, and occasionally fine rootlets. The female gathers bits of material, flies to the box, and arranges it inside. To form the hollow in the nest, she will sit inside it and press her breast up against the sides. This is called molding. In some cases the female bluebird may be assisted by juvenile bluebirds as she builds her nest. They may have been her young from a previous brood.
Bluebird nests are airy and light but well built, and have a small, neat cup shape in the center. The center may be lined with finer grasses or rarely just a few bits of hair or feathers. Second broods or second attempts can occur in the same nest box; a new nest is just built on top of the old one. Sometimes old material from the previous nest is removed by the birds, but they will not try to remove the whole nest.
Since we are monitoring the boxes, we will be removing all nesting material after the young have fledged or immediately after a failed nesting attempt. This keeps the nest box clean and allows the new nest to be the proper height from the entrance hole.
As we think spring is just around the corner, some of our hardy fellow gardener's have been preparing their garden beds for spring planting by digging them up or turning the soil in the beds. The birds love this as they are the recipients of these fat, tasty grub worms that you see in this feeder on the garden fence. We want say which beds these healthy worms came out of, that will be our secret. Thanks to those who have been walking the bluebird trail and taking photo's and notes of all that is happening on the trail.
This is the week that we start our monitoring of the activity and nest building of the 20 nest boxes along the bluebird trail. We will start recording and reporting the details on The Cornell Lab of Ornithology website.
In our next blog we will give you the activity and up dated information of what is going on in each of the 20 nest boxes. Keep the photo's, notes, comments and support coming, as it helps me a lot with keeping up with all that is happening along the bluebird trail.
You Can Help! Become a friend of the Bluebird Trail at the Green Meadows Preserve Community Garden.
Make your checks payable to MGVOCC/Green Meadows Community Garden
(Master Gardener Volunteers of Cobb County)
Mail your sponsorship to: Jim Bearden
1648 Oakford Court
Marietta, GA 30064
For questions:
Call Jim at 404-202-8755
We are a non-profit 501-3C organization, so your donation is tax deductible.
Thank you for being a friend and a big part of the conservation solution!
