Why Worry?

... proclaimed the nomadic Brown-headed Cowbirds, Molothrus ater, and stopped looking for nesting material. 
We are on a constant move, following the countless herds of bison, there is no time to be wasted by nest building, incubating and raising the young. That takes weeks and the bison won`t wait
Okay! No fear - we shall lay the eggs into someone else's nest. Or nests .... more the merrier.  
Each female will produce 20 to 35 or even more eggs each summer and lay them - one by one into different nests. That should be sufficient for the survival of the species. 
We shall choose the smaller bird species to raise our young so that their young cannot really kick out our babies out of the nests. On the contrary.

Brown-headed Cowbird - Male

Meanwhile we shall roam the American continents, picking insects, grass seeds and such. Being adaptable we shall grow in numbers and then ..... hmmm,... then.... what?
Oh, never mind ....

And so it happened that the cowbirds, just like the cuckoos and several other species became brood parasites.

Brown-headed Cowbird - Female

Well, this of course is my grossly simplified version of the long-time evolutionary process but these days most everyone understands the paralell. 

The fact is that the cowbirds became very good at laying their eggs into the cozy nests of songbirds. They are not too choosey - the reports state that the cowbirds already use some 240 different bird species as their involuntary hosts. Each female lays only one egg into a host nest. But then her sister and a cousin and several other female cowbirds can choose the very same nest.



 

It happened yesterday, July 27th, that we noticed a pair of small birdsrunning (yes, running) their legs off all over the driveway, and picking up seeds and bugs.
They were Chipping Sparrows,  Spizella passerina, 

 Right on their heels ran three other birds - twice the size the sparrows - relentlessly demanding to be fed!



 

NOT ENOUGH!

So the caring sparrows, their rusty caps all ruffed up and their wings and legs tired, kept on running and flying and feeding their "offspring". The fact is that the cowbird babies raised in their nest kept them so busy that they never realized that their own offspring was dispatched and done with a long time ago.


Just like all youngsters, the cowbird fledglings must learn about the world they were born into. The roosters were frightening but, thankfully, they soon motored away.

 

But something had been left behind and one of the young had to explore! 

Good to eat? 

 
Too large. How about this one?



 Negative! 

Better find the parent and demand real food! 

















The sparrows obliged. Over and over again they filled the bottomless pinkish caverns with all the food they managed to find.

It won`t take much longer, perhaps a couple of days, and the young cowbirds will become fully independent. 
The sparrows will fluff their feathers, relax for a day or two and possibly begin another courtship. 

Lets wish them better luck next time.






The fledglings will mature find their places in cowbird flocks and  continue to conquer the continent. 
They were originally found only in the prairies preying on the insects disturbed by the great hooves of countless bison. But the bison are gone. Places all over are being deforested, spaces are being open for non-arboreal species. 

The adaptable nomads are successfully learning to utilize the new environments; much to the detriment of songbirds whose nests they seek.