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Title: Deadbeat birds Written by: bio_man on May 11, 2018 (https://biology-forums.com/gallery/37/6_11_05_18_9_23_42.jpeg) (https://biology-forums.com/index.php?action=gallery;sa=view;id=37563) Brood parasites are organisms that rely on others to raise their young. It's the equivalent of having a baby, placing him/her in a basket, and then leaving it on a random person's front porch. While this may seem strange to us, it's not uncommon to some species of birds. One of nature's shrewdest examples of this behavior comes from cowbirds. Not only do they lay their eggs inside the nests of other birds and expect them to rear the foster chicks as their own, scientists have found another way these birds may be harming their hosts -- their extra-thick eggshells can crack the hosts’ own eggs when they falls into the nest. To test this idea, researchers of recent study (https://academic.oup.com/beheco/advance-article-abstract/doi/10.1093/beheco/ary045/4975423) gathered 157 freshly laid cowbird eggs and dropped them onto host eggs from a height of 6 centimeters. The scientists also reversed the scenario, dropping host eggs from wrens, mockingbirds, and blackbirds onto cowbird eggs. Cowbird eggs were almost immune to cracking in either scenario, with a mere 3.6% chance of getting damaged. But the cowbird eggs managed to crack their hosts’ eggs about 10 times as often. In the wild, laying these deadly, thick-shelled eggs cunningly eliminates would-be food competitors from the nest before they even hatch. https://www.youtube.com/watch?v=m_bboLNi550 |