The adult robins are very patient with us. Lello (named after Melanie’s brother, Raffaello) and Christmas girl (she has dark green and red bands) live in a glut of vines and matipo on West Landing. They are super friendly and very trusting. Nevertheless, they like to watch us when we weigh their babies just to make sure we are gentle. Not that we can really call their chicks babies anymore – they are so big now! Here you can see one of Lello’s chicks at 3 days old, at pin-break (when their feathers just start to show) and at banding age (16 days old); going from 4 grams to nearly 27 grams in just 12 days.
Lello's chick showing her bands - 16 days old:
Why do we collect this growth data? It is an important part of Melanie’s research to compare the growth rate of Rangatira songbird chicks to the growth rate of songbird chicks on mainland NZ. The speed at which the chicks grow up and shift out of the nest depends on the safety of their environment. Mammalian predators, such as rats, cats and stoats really like baby birds for breakfast, lunch and dinner! The more hungry predators there are, the more dangerous it is for chicks to spend a long time in the nest. Every day they spend in the nest increases the chance that they will be discovered and eaten by a predator.
Lello's chick at weighing time - at pinbreak stage:
Lello's chick at weighing time - at pinbreak stage:
So, if there are lots of hungry predators lurking around in the forest, it is a much safer strategy for chicks to grow very fast and lave the nest as early as possible! European songbirds, like blackbirds and starlings, have evolved in Europe alongside predators for a very long time (we are talking about millions of years here!) have developed this strategy: grow fast and get out of the nest! For example, a blackbird chick on mainland New Zealand will leave its nest after only 14 days, while a black robin chick on Rangatira Island will typically stay in its nest for 22 days! What do you think is the better strategy if there are lots or predators out and about?
Lello's chick at 3 days old:
(This blog was written by Melanie and Alex)
Hi - great to see the work happening, but some suggestions re: your video,for next time: get in close. The viewer never sees the chick, only a bunch of people in the bush.
ReplyDeleteAlso, turning a way while talking means the viewer loses track of what is being said, and eye contact is lost too.
Otherwise, very interesting! Cheers. Jeffrey.