Page 12 - Discover Spring 2021
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Bluebirds CONTINUED
the post with something that will deter snakes. are typically blue in color, and she will not begin to
incubate them (sit on them) until the last egg has
If you want to build your own birdhouse,
been laid. The eggs will begin hatching within two
remember that the hole of a bluebird house should
weeks, and will hatch within hours of each other.
be no larger than 1 ½ inches. This is so that a
The brood will leave the nest within 20 days after
bluebird can easily slip inside, but a starling cannot
hatching. When they leave, they will be nearly the
because they are too large. The European starling
size of their parents.
competes for nesting sites with the bluebird. The
bluebird has a slight advantage because they nest Mom and Dad will continue to care for their
earlier, but they are no competition when it comes to young after they leave the nest, giving them flying
a fight with a starling over a nesting hole. So make lessons and teaching them how to forage for food.
sure that the starling won’t fit through the hole in Then, within about a two week period the male
your birdhouse. bluebird will take over the job, while the female lays
another batch of eggs and incubates them. He will
Unfortunately, sparrows also compete with
feed her while she is sitting on the eggs. Interestingly,
the bluebird for nesting sites. They may try to take
some experts say that the fledglings from the first
possession of your bluebird house. If that happens
brood actually help with the feeding of the next
and you want to stop them, you will need to clean
group of hatchlings.
out any nesting material put in by the sparrows
each day until they finally get the message that they Another interesting thing that scientists have
aren’t welcome. Be forewarned – these little creatures discovered is that female bluebirds have a “brood
can be very determined. It will take dedication patch” that forms during mating season. This patch,
and perseverance to discourage them, once they’ve which is featherless, is on her stomach and only the
decided to nest in the box that you intended for female bluebird has it since she is the one who will
bluebirds only. If all else fails, you may want to cover incubate the eggs. This bare patch contains blood
the hole and wait until later in the year to open it vessels that are very close to the surface of her skin
and try again for bluebird tenants. and can thereby supply the eggs with the amount
of heat necessary for them to hatch. After breeding
Another neighbor here at the lake put up
season is over, feathers grow back over the patch until
a bluebird house on a tree, and it soon became the
the next breeding season. In some species this brood
home of a flying squirrel and her family of three
patch is found in both male and female birds because
or four babies. There were no complaints from the
both take part in the egg incubation.
property owners that she wasn’t a bluebird; watching
her “fly” from tree top to tree top was a delightful Scientists also say that the color of a bird’s
experience for them. feathers depends upon the structure of the feathers
and how they reflect sunlight, along with the quality
Bluebirds nest two to three times in a year,
of nutrients that the bird has received throughout its
beginning as early as February but typically in
life.
March, depending on weather and the availability
of food. The male finds a nesting site and then sings However, color change happens chemically as
to attract a female and to warn other males away. well. Some feathers are colored by pigment deposits,
Once a female accepts the site, she will build the making males their most colorful when they’re
nest, which is circular in shape and made of dry looking for a mate. The more brilliant the color, it
grasses and pine needles. It will take her from five has been proven, the more beneficial he will be to
days to three weeks to build. Once the nest is built, his offspring. What has taken years for science to
the female will lay one egg per day until she has learn, the female bird has known all along: the more
laid from three to six eggs. Again, the number of vivid and beautiful the mate, the better the catch,
eggs depends on the availability of food. The eggs genetically speaking.
10 Discover Smith Mountain Lake SPRING 2021
