In eagles that's called the Cain and Able syndrome... eagles typically have two fledglings, but the stronger will push the weaker out of the nest.
Oh my gosh, my pigeon laid 2 eggs!
He will be fine if hes not strong enough to fight off his sibling then i will put in the other nest.
Both the parents will feed them both i've had to do this once or twice.
Once i had to remove the big baby at certain feedings so the smaller one got a crop full and put the other back at the next feeding.
It's rare that this happens i don't know why it did these are my white fantails and they raised at least 7 or 8 pairs last year. Not one of those was like this they were both the same size has to be the weather throwing off thier egg laying.
Well there won't be anymore babys here until spring.......
Oh yes, you must be right! The cold weather maybe delayed its development or something and now it's having to compensate. Poor little pidge. That is what I always call mine "Such a pretty pidge!" I remember your photos of the white fantails...gorgeous...
usually that only happens if they start setting on the first egg rather than them start together on both after the second is laid. if they do it causes a speratic hatch and one will be born first so that will be the bigger piggy of the clutch and the second baby will be behind.