Do birds stray?

[rutineli]

As is common knowledge, a dog on heat will be attracted by any canine bitch and no doubt a tom cat with the urge to mate will not ask to see the birth certificate of a passing pussy cat.
What about birds though?
To us a bird, although of diverse sizes shapes and types, is nonetheless a bird, but when they are taken by the need to procreate do they ALWAYS stick to type? Or, does a robin ever sneak a quick one with a chaffinch , or a blackbird with a thrush? Will a sparrow settle for a tree creeper or vice versa?? How about a blue tit for a green tit or a gold finch for a green finch - well you get my point. Wood pidgeons and town pidgeons or doves??
- rutineli

[wildwood]

'Birds' covers about 8600 different species. Their sexual habits cover the full range of preferences.

Apart from the very odd occasion when a bird has had a traumatic experience or is associated with humans, they pretty much stick to their own species. Evolution adjusts specific alterations to species by small mutations in unison with their environment, not cross breeding.

Generally, species within the same genus can have offspring, but are mostly sterile so mating outside your own species is a waste of energy.

As for the odd bonk, most birds are broadly divided into two categories; monogamous and polygamous. The monogamous ones stay true to their one mate. The polygamous ones will have more than one mate and would think nothing of having a jump on one his neighbour's hens if he gets half a chance, as long as it is the same species.

[rutineli]

Wildwood please accept my genuine gratitude for your extremely informative and interesting answer. It was one of those questions that had wandered aound my mind for years. - rutineli