Nope, it's not the weather this time... it's birds laying eggs that fool mom.
Imagine trying to raise a baby who's grown twice the size of yourself! Other nestlings in the group haven't fared so well because the big one hogs most of the food. This actually happens often- no thanks to the brown headed cowbird.
Considered parasitic eggs, because they're literally dumped in the existing nests of unsuspecting birds. It's the natural instinct to thrive, though cowbirds won't be bothered raising their own. Considered nomadic, they tend to follow livestock herds for the abundant insects, their habitat being open grasslands and meadows (too far away from nests).
Most birds are unaware that an imposter is looming, and end up raising the ridiculously large intruder to the consequence of other nestlings.
A bit smaller than blackbirds, cowbirds have brown heads. They prefer to deposit in an active nest with at least two eggs smaller than their own. Bluebirds, Carolina wrens, and warblers are most susceptible. This is just one reason why it's so important to use correctly proportioned birdhouses. Those gaping entries on some inexpensive, decorative houses found in hobby shops tend to invite not only 4-legged and winged predators... but imposters to the detriment of songbirds.
And should you like to become a really, really good landlord- monitoring nests actually helps backyard birds thrive. This April Fool's is a sad one indeed :(
