I am very sorry about your loss. It is heartbreaking to get chicks to the point of weaning and then lose them. First, please remove the nest and discard the new eggs. Your pair needs a break from breeding, and if you let them hatch eggs now, you will probably see a repeat of this tragedy. It’s too hard on them to go through all of this, and too hard on you.
As to why and what happened, it sounds like the poor chicks were not weaned and taught how to eat by the parents and they starved to death. Birds have a very high metabolism, which means they eat a lot for their body size and they have to eat often. At night they survive by lowering their metabolism, but once awake, they need food very soon. A small bird like a finch can die from going only a few hours without food. Their digestive system responds to a lack of food by shutting down, so even if the bird gets food after this happens, he dies anyway unless he received a special liquid critical care formula. Sadly finches and similar species do not automatically know how to self feed. Wildlife rehabilitators always try to raise these type orphans with similar species that are already self feeding. Otherwise the rehabber has to tap the syringe or feeding implement in the seed or insect mix while the chicks watch, and eventually the chicks mimic the syringe and learn to eat. This is a tedious process and can take days to work, meanwhile the chick still gets hand fed.
Why did the parents fail here? There can be many reasons. Are the parents too young? Finches should not be allowed to breed until they are over 1 year old. If they are too young, they are often more interested in the mating aspect and will end up neglecting their eggs or chicks in favor of breeding again and laying more eggs. Even an older pair will do this, so it is always important to remove the nest as soon as the chicks have feathers and have left the nest. This will allow the parents to focus on weaning their chicks instead of going back to nest again too soon. Was this their first clutch? If so, first clutches almost always fail due to improper incubation, not feeding the chicks, or not following through and weaning the chicks. It is sad, but it’s important to leave it to the parents to learn, so that they can be good parents to future clutches. However, if this happens again and again, the pair should not be allowed to breed again, as some pairs never make good breeders or parents. Have they been over bred? As I mentioned before, the nest should be removed once the chicks have left it, to prevent the parents from breeding again too soon. In the wild, small species like these will have 1 or 2 clutches at the most, once a year during breeding season. In captivity, it is up to the owner to remove the nest and limit a pair to two clutches per year so that they do not get worn out by breeding year round. The pair should be rested for several months between each clutch. They do not need a nest except when they are breeding and laying eggs. Adult birds do not sleep in a nest – they only use it during breeding season. When a pair is allowed to breed too often in captivity, it is hard on their health, and the chicks are less healthy. The parents will also get too worn out and not care for the chicks properly. Lastly, do they have the proper nutrition they need for breeding? You should be offering them a pellet that is formulated for finches – a loose seed mix is not adequate. You can also offer chopped veggies and for some species, a dried insect mix. For breeding, also offer cooked eggs, with the shell washed, crushed and cooked with the eggs. This egg food is also something the parents will teach the chicks to eat, along with the pellets and fresh veggies. If your pair only eats seed, then you need to get them on a better diet before you let them breed again.
I hope you can rest this pair for a few months, make sure they are on a good diet, and then maybe they can finish their job next time and teach their youngsters to self feed. If not, then I would not breed these birds again.
Thank you for asking Lafeber,