Nov 172013

On July 4th I discovered an Abert’s Towhee nest with five eggs.  The next day the towhee had laid another egg.  Altogether there are:

2 Abert’s Towhee eggs

1 Bronzed Cowbird egg

1 Brown-headed Cowbird egg

2 from an unknown species

Because Brown-headed Cowbirds eject the eggs of their host, there is no way of knowing how many eggs were actually laid by the towhee.

Note in several shots you can see one of the eggs has a peck mark on it, very likely the work of a Bronzed Cowbird.

The Bronzed Cowbird’s egg is the single largest all white egg.

The small dark heavily speckled egg belongs to the Brown-headed Cowbird.

The Abert’s Towhee eggs are the two large eggs with black speckles on the end.

I have tried, without success, to get the two small white eggs identified.

On the 15th one of the two small eggs was pushed out of the nest.  Here is  a different angle of the 7/15 nest.

I was interested in the treatment of the eggs by the host.  Here is a graphic.

DENT and NODT are the two unidentified small mostly white eggs.

The graphics directly follow the photographs above.

It can’t be determined whether the ABTO eggs got preferential treatment and based on what I have read the eggs are turned multiple times a day.

Although the photo of July 16th shows just one chick, actually two hatched, the BHCO in the morning and the first ABTO in the afternoon.

Abert’s Towhee — Chapter 1

Brown-headed Cowbird — Chapter 2

Bronzed Cowbird — Chapter 3

Hatchlings — Chapter 5

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