Last week I mentioned that our friend Margie Wing had called to report the first mountain bluebirds had returned to Indian Hills on Tuesday, Feb. 12. For lack of space, I said there would be more about them this week. Little did I know that would be the last conversation I would have with Margie. After a brief, courageous fight with cancer, Margie left this world on Friday, Feb. 15. I hope she is surrounded with bluebirds, hearing their soft, sweet warbling song.
Yes, I feel sure Margie heard them that day. She was gifted with an exceptional musical talent and was, therefore, great at identifying birds by song. Although Feb. 12 is a bit on the early side, they do sometimes arrive that early, and it was an exceptionally warm spring-like day. Perhaps they came to say farewell to Margie. We will miss her very much.
Mountain bluebirds winter in large numbers in the plateau country of southern Colorado and northern New Mexico. A few are seen every year on the Christmas Bird Counts in Colorado Springs and Pueblo. We assume these early-February records are scouts or pioneers, which return to the flocks to report whether they should start north or not.
However, there is no solid data to prove this theory, but these early bluebirds seem to appear on nice warm days and then retreat when the next snowstorm comes. Then they reappear with the next warm spell. To prove this would take an incredibly lucky break of getting a series of reports on banded birds, which is not likely to happen.
We know that large flocks of bluebirds congregate along the Arkansas River in spring, and if the weather is fair, they arrive here a few days later. We also know they are sometimes caught in early-spring snowstorms. Occasionally, they seem to be on shrubs and fence posts along every road, so brilliantly blue they look like a piece of Colorado sky against the snow. If the snow melts within a day or two, they seem to find enough food to survive. If it lasts longer, they seem to disappear. Perhaps they drop down lower onto the plains, perhaps they return south or perhaps they die. We just don’t know for sure, but no one has found large numbers of dead bluebirds after these brief spring snows.
Although bluebirds are largely insectivorous during the summer and feed their young entirely on insects, they survive all winter on juniper berries, other frozen fruits and very few insects. Such food also sees them through brief snowstorms as well.
By the first week in March, many of the resident mountain bluebirds have returned to this area. In years when winter hangs on a bit later, they may not return until March 15. During this time, many migrants also are moving through, heading farther north. This leads to constant squabbling over nesting cavities. The bluebirds may put a few blades of grass in their chosen cavity (or nest box) but do not seriously start building until April. By late April, their nest is finished and their first clutch of eggs in usually laid during the first week of May. If driven from their chosen cavity by starlings, house sparrows or swallows, they will try to find another site and rebuild.
Therefore, it pays to have a few extra nest boxes in your yard. Place them at least 300 feet apart, as bluebirds do not like close neighbors. Due to the pruning of dead trees and limbs to help control forest fires, natural cavities are scarce; therefore, secondary cavity nesters will use it for a second nesting, or it may be used by chickadees, nuthatches or violet-green swallows. If your boxes are old and have been used in the past, they must be thoroughly cleaned. Bluebirds will not use a dirty cavity that contains an old nest.
The annual Audubon Society bluebird box sale will be on March 8 and 9 this year — a bit later than usual — but if you put the boxes up right away, it will still be in plenty of time. This year’s boxes are a bit more expensive ($25), but they are bigger, to give the bluebird more tail room, and they are better made, out of quality cedar boards. They also made fewer boxes to sell this year, so get there early, for they are likely to sell out. Boxes will be sold at area Safeway, King Soopers and Albertson’s.