Monday, 6 June 2016

Egg Fraud

The gooseberry bushes, planted decades ago by my parents, have become badly overgrown with grass and weedy shrubs. A couple of days ago I made a mental note to bring out my pruning sheers and tidy up the mess. But just as I eyed a honeysuckle plant that would be on the hit list, I noticed that it held a dainty little nest, containing two delicate eggs. It belonged to a pair of Yellowthroat warblers. She flew off the nest and then scolded me from a nearby branch. Trimming will have to wait until the nesting season is over.

 A female Yellowthroat warbler waits for me to leave before returning to her nest.

Her tidy little nest held two dainty and speckled eggs.

A male Yellowthroat warbler challenges his reflection in my window.

This afternoon I noticed that the Yellowthroat nest now has four eggs. But something is not quite right about the clutch. One egg is noticably bigger than the others and patterned a little differently. It belongs to a Brown-headed cowbird. Bad news for the Yellowthroats! The illegitimate cowbird egg means almost certain death for the warbler young.

Three Yellowthroat warbler eggs and one Brown-headed Cowbird egg.

Brown-headed Cowbirds lay their eggs in the nests of over 200 bird species, sneaking in at daybreak and quickly depositing an egg as well as throwing out an egg belonging to the host. Red-winged blackbirds are capable of raising both their own young as well as that of the cowbird, but this is seldom the case of the smaller host birds.

Each female cowbird is capable of laying dozens of eggs per season. She never builds a nest or cares for her young. No Mother's Day cards for her!


  1. Your photos are beautiful Florence. Interesting this issue of the cowbird's laying habits arose at your property; there are a number of forums online discussing the ethics/legalities of removing the cowbird egg from nests all over NA. More research is probably needed to know the true impact of the cowbird's habit. I notice two of them at my feeders from time to time. Hmmm

  2. What a hoot, they are. Good eye spotting them. I love these birds, too. Did you leave it in there?

    (ツ) from Cottage Country Ontario , ON, Canada!

    1. The cowbird egg is still in the nest along with the legitimate three eggs. It would likely be illegal to tamper with them and unethical to save the warbler babies by shaking the cowbird egg to addle it. (No witnesses, no confession, wink, wink.)


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