Why is my male bird building multiple nests in different pots?

When zebra finches are all white it is sometimes hard to tell if they are male or female as they won't have the characteristic cheek markings, beak coloration or tail patterns. The two pictured look like they could possibly both be female, but it is hard to tell due to the distance from the camera and the lack of markings present (males will sometimes still have darker cheek areas, a stripe on the cheek, or a darker red beak). Males will also sing almost constantly that sounds quite different than regular chirping, and will also "tail waggle" when they are wanting to/attempting to mate with a female. If none of your birds are doing this, it is possible they are all female. Both males and females will show interest in nests and will go in them to sleep at night even if they aren't raising babies. If one is being left out, you can add in another nest or sleeping area to see if it helps.

Parakeets don't usually try to mate with things other than other parakeets, however if he is doing this behavior with you it is best to just put him back in the cage and let him go about his business until he has calmed down. You can still interact with him by offering treats or having him sit on a perch instead of your hand if the behavior continues. If they're both males (which is always possible) it may be they aren't interested in the nest. You can try adding some items to it to make it more interesting, or offer some nest building material (most pet stores will carry this) to see if it encourages nest building. Be sure not to place yarn or other strings as feet and beaks may get caught on that and cause injury.

It would be best to separate each pair into their own cage as the birds may begin to fight over territory, food and water, perches, and shared nesting areas, which could lead to injury. If you don't wish to have babies, removing the nesting material and any eggs should resolve the issue. If you do wish to breed them, making sure the birds have a calcium supplement such as a cuttle bone can help prevent egg binding and produce healthier eggs in addition to a regular balanced diet.

Thank you for using Petco Pet Education Center, formerly Petcoach! The signs you describe are consistent with over grooming, likely from the other bird. This may be due to boredom or overly dominant nature of the cage mate. You can try to provide additional toys and perches in the cage, keep the light cycle in the room stable, and provide a nesting box. I hope this helps and am happy to answer any other questions you may have!

If the aviary is too small to handle multiple breeding pairs it may be that they are competing for nesting space, even if there are multiple nests. One nest may be seen as "ideal" and thus everyone is fighting over it. Usually, birds are separated into individual breeding groups per cage to avoid competition and ruining of eggs, as well as reduce overall stress for the breeding pair.

Finches do best in pairs. Keeping them with budgies would not be recommended since they may get bullied. Finches also require longer cages that allow them to fly about, while budgies do fine in taller cages because the like to climb.

Males can help sit on the eggs, or may offer food/support to the female so that she can still be fed and active. This is very normal behavior, and as long as both are taking care of themselves and the eggs and do not seem stressed out, I would not be worried. If the male is harassing the female to the point that she seems stressed, or can't get food or water, then separating the two for a time may be best.