# Do different species of little birds ever hump and/or have eggs together? **URL:** \ **Category:** Factual Questions\ **Created:** [July 9, 2018, 2:10pm UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570 "2018-07-09T14:10:12Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 9, 2018, 11:35pm UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570/21 "2018-07-09T23:35:39Z")
> [@araminty](#): > > Hopefully Colibri will be here soon to post one of his excellent explanations of speciation/hybridization. As a birder, I’ll point out that hybrids do occur in nature. Notably, at least here in CA, within Anatidae (ducks) and Parulidae (warblers). > > [Waterfowl Hybrids | Ducks Unlimited](http://ducks.org/conservation/waterfowl-research-science/waterfowl-hybrids) > > [https://audubon.org/news/the-amazing-world-hybrid-birds](https://audubon.org/news/the-amazing-world-hybrid-birds) Most closely related species have evolved differences in courtship behavior (calls, displays) that prevent mating from ever taking place. It is believed that this is because hybrids are in some way less capable of surviving and producing offspring, so that individuals that are willing to mate with members of other species are selected against. In fact, this is why courtship behavior exists in the first place: so that two members of a pair can determine that they are in fact members of the same species, and will produce offspring that won’t be selected against. This can break down in captivity, or in places where one or both species are rare, and no other member of their own species is available as a mate. Basically, it’s “beggars can’t be choosers.” In such cases hybrids, even completely fertile hybrids, can be produced. But the requirement for recognition as distinct species is that such hybrids are rare or don’t occur under natural conditions, not that they are sterile. The more time two lineages have been separated, the less likely they are to be able to produce fertile hybrids, as genetic differences accumulate between them. Eventually they will be unable to produce viable hybrids at all, even sterile ones. But this process takes time, and sometimes only distantly related species like camels and llamas may still be able to produce hybrids. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 9, 2018, 11:38pm UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570/22 "2018-07-09T23:38:07Z")
> [@Enola\_Gay](#): > > My personal definition of successful breeding would be production of offspring that can survive. So by my definition, a mule qualifies, even though they are sterile. No biologist would regard that as “successful” breeding. In evolutionary terms, producing sterile offspring is even worse than producing no offspring at all, because the individuals put time, effort, and energy into producing an offspring that was a dead end. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 10, 2018, 12:31am UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570/23 "2018-07-10T00:31:58Z")
> [@Enola\_Gay](#): > > My personal definition of successful breeding would be production of offspring that can survive. So by my definition, a mule qualifies, even though they are sterile. > > And yes, African & Asian elephants would never meet up in the wild. Motty (the only known hybrid to have survived to birth), was born at a zoo & died after a few hours. My theory is that if 2 animals can successfully breed & have access to each other, they will. If an expert comes along & tells me I’m wrong, I’ll change my position, but if a cardinal & a finch could breed, there would be a card inch in my bird book. With all due respect, this being GQ and all, your personal opinion doesn’t mean much. Biologists have a definition of what a species is, and the most commonly used definition for animals is the Biological Species Concept. If two populations regularly interbreed and produce fertile offspring in the wild, they are usually considered the same species. If they don’t interbreed (or rarely do so), they are considered separate species. If two population can interbreed and produce fertile offspring, but they don’t do so because they are separated by some barrier, they will usually be classified as subspecies. There are also ring species, where several populations have overlapping territories. Imagine 4 populations A, B, C and D such that A can interbreed with B, B can interbreed with C, C can interbreed with D, but A can’t interbreed with D. You do get gene flow between A and D, but not directly. ETA: I started this before **Colibri** posted and just realized I didn’t finish. Most of this I learned from him, so hopefully I got it right. 🙂 ---
**Author:** ![Enola\_Gay](https://avatars.discourse-cdn.com/v4/letter/e/3ab097/32.png) [@Enola\_Gay](https://boards.straightdope.com/u/Enola_Gay)\ **Post date:** [July 10, 2018, 1:40am UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570/24 "2018-07-10T01:40:05Z")
> [@John\_Mace](#): > > With all due respect, this being GQ and all, your personal opinion doesn’t mean much. My apologies. I was responding to a question where someone asked me what my definition of successful breeding was. Since I am not a biologist, I probably should not have answered. ---
**Author:** ![drewder](https://avatars.discourse-cdn.com/v4/letter/d/57b2e6/32.png) [@drewder](https://boards.straightdope.com/u/drewder)\ **Post date:** [July 10, 2018, 2:09am UTC](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570/25 "2018-07-10T02:09:31Z")
Sorry by viable i meant to say offspring capable of reproducing. [Previous page](https://boards.straightdope.com/t/do-different-species-of-little-birds-ever-hump-and-or-have-eggs-together/817570.md?page=1)