Most birds build their own nests and incubate their own eggs. However, some birds like the cuckoo have managed to get around this inconvenience by simply laying their eggs in the nests of other species and letting someone else do the hard work of keeping the eggs warm and protected until the chick hatches. The 'host' (the poor sucker who ends up taking care of the other birds' eggs) does everything they can to try and make sure the eggs that they're sitting on are just their own. On the other hand, the 'brood parasite' (the freeloader bird that just lays in the nests of others) does everything they can to make their eggs indiscernible from the eggs of their host.[caption id="attachment_433" align="alignleft" width="300" caption="See if you can spot the parasitic cowbird egg in this nest"] [/caption] [More]














Source: Birds arrange eggs in their nests to better detect imposters