Tuesday, May 14, 2013

The relative cowbird

 We have heard a new bird song in the morning. It is a nice song - strong, "a liquid-sounding series of low gurgling notes followed by thin sliding whistles". It is a unique song. I watched the birds, looking for the one singing those gurgling notes. 
It comes from a brown-headed cowbird. The house finches, goldfinches, sparrows and lovebirds all tolerate this visitor. He seems innocuous enough... but I am not sure I am pleased. 

Cowbirds are brood parasitic birds. They lay their eggs in other birds' nest. Their young are fed and raised by the 'host' parents. If the host 'knocks' the cowbird egg out of the nest, the adult cowbird may/often return to destroy the host's own eggs. 

It "seems that Brown-headed Cowbirds periodically check on their eggs and young after they have deposited them. Removal of the parasitic egg may trigger a retaliatory reaction termed "mafia behavior"." (Hoover, Jeffrey P. &. Robinson, Scott K. (2007). "Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs". PNAS 104 (11): 4479–4483).

So it seems odd that the other birds at our feeders and in our garden sit along side the cowbirds. They eat side by side, they hop around on the grass together.  They don't fight one another, nor do they scream or dive-bomb each other.

 (Photo above shows a cowbird and a lovebird sharing a tree)

Cowbirds might be like some relatives... drop the kids and run. And I wonder whose behavior came first - the bird's or the relative's
You can bet I will be watching bird behaviors more closely now...
 

7 comments:

Chris Rohrer said...

Great pictures! I love these birds but I especially love their alien gurgles:) Very pretty sounding!

Jo's World said...

Not sure I would like this guy either. Never expected to hear the word "mafia" in connection with a bird!

Jo

Banjo52 said...

I have at least two cowbird families this year. I know their reputation, though I always forget the details, except to say they strike me as Wall Street Republicans.

When we had a rat last fall, I was surprised to see the birds eating beside him as if he were another bird. Of all "people," only the dove expressed alarm, by raising one wing toward the rat, as if to shield himself or threaten the rat. .

One could do worse than studying birds . . .

altadenahiker said...

I've got some visitors that sounds like an old fashioned adding machine. They only sing (or whatever) really early in the morning, so have no visual reference.

Pat Tillett said...

Not only fantastic photos, also very interesting info. I had no idea...

Celeste said...

I'm totally with you, I always have very mixed feelings when I see Cowbirds.

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