What's
unusual?
By
Laura Erickson
Robins normally lay four eggs, and this nest has SIX!
The person who took this very special photo said the nest seemed to be deeper and narrower than robin nests he saw before. Was the nest made by a beginner? If so, did her inexperience cause her to make the nest a little deeper than would be best? Or did another robin lay an egg or two in her nest?
Photo Wayne Kryduba
What do
YOU think will happen to the six eggs?
Find
out >>
Birds don't
count when they lay eggs. Part of the stimulus for a mom to know when
to stop laying eggs MAY be the feel of a full clutch on her abdomen,
where her brood patch is. Robins hardly ever lay more than 4 eggs,
and scientists think that just about any time there are more than 5
eggs, another robin laid the extras. I think in this case, because
of the odd shape of the nest, the eggs may all have been laid by the
same bird.
Do you see the egg that is lowest in the nest? Usually the nest floor is
flat so all the eggs are the same distance from the mother's brood patch.
It's going to be interesting to see what happens in this nest. Here's my
guess:
-
That bottom egg may be too low to get the same amount of heat as the other eggs. If so, it may not hatch.
-
It may take longer for the other eggs to hatch because they are closer to the mom's sides than to her belly, where her brood patch is.
The cool thing is that I can make these predictions from knowing a lot about robins, but I don't know the answer. Nobody does!
A scientist could learn a little more by taking DNA samples from the chicks after they hatch (or from the eggs that don't hatch), to figure out if only one female laid all of them. But even that wouldn't tell us whether one robin could hatch all six eggs and the pair could raise them all. All we will ever know for sure is just whatever happens. (All the facts we know about birds are not absolutes. They are based on statistics and averages.)
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