Cowbirds are famous to lay their eggs in other birds nest and surrogating them to be hatched and taken care off. It remained elusive how cow birds manage this approach. Recent research in Behavioral Ecology proposes that “thick egg-shells” of cowbirds laid in the nest raises the vulnerability to break “thin-shelled eggs” of surrogate bird. While previously it has been shown the Robin primarily reject cowbirds’s eggs by intentionally breaking the shells. These ticks are worth a matter of how birds evolve over the need.
, ary045, https://doi.org/10.1093/beheco/ary045Thick eggshells of brood parasitic cowbirds protect their eggs and damage host eggs during laying Behavioral Ecology