Birds don’t leave the nest randomly but pick the ideal moment when this should happen. If the younglings leave their parents too late, they put the whole brood in danger, but leaving too early has its disadvantages as well. Therefore, researchers decided to study how the needs of young birds and their parents clash.
When should birds leave the nest?
Before birds leave the nest, they need to make sure they have acquired all the traits necessary to survive. If they spend more time with their parents, their wings develop better, while they also become more capable of escaping danger. However, an advantage for the young bird might mean a disadvantage for the brood. Every extra day it spends in the nest increases the levels of danger, as the whole brood risks getting eaten.
Researchers realized the needs of young birds and those of their parents might be different, so they decided to study when they should leave the nest. For this, they selected 19 species of songbirds native to the US and started making some observations.
Different fledging times have different consequences
They looked at the time these youngsters needed to develop, as well as the statistics on nest predations. Afterwards, they selected 11 of the species and performed advanced observations using Go-Pro cameras. With the cameras, they looked at their flying skills and the age when they left the nest.
If they chose to leave the nest early, their flying performance was poor and were easier targets for predators. Then, they performed a few experiments where they allowed young birds to leave the nest naturally but kept them protected for a few days. Even so, those who fledged too early were less likely to survive.
Now, you might think these birds should evolve a longer nesting period. However, older studies proved nests are easier targets for predation the more they stay occupied. If they get attacked, the whole brood is in danger. This way, parents promote early fledging, since some younglings manage to survive. Therefore, bird parents try to convince their young to leave the nest as soon as possible for everyone’s safety.
The study birds that leave the nest was published in the journal Science Advances.
Image source: Max Pixel