Dear Readers, I have mentioned before that my garden is inundated with fledgling starlings every year. To start with it’s just one or two but by the end of May every bough is bending under the weight of squawling youngsters. When I look up, I see adult starlings with their offspring in hot pursuit. It’s a difficult few weeks for starling parents, to be sure. To start with, the youngsters are completely clueless, standing ankle-deep in food without knowing what it is.
Somehow the adults seem to know which ‘child’ is theirs, and they only ever feed their own offspring, regardless of the pitiful cries of other youngsters. I wonder if they know by the tone of voice, or by some subtle visual signal? The little ones all look the same to me. Most starling parents seem to have two fledglings on average, though some exhausted parents have managed three – they probably started off with four eggs. And they might not even be their own chicks – starling mothers will sometimes lay an egg in a neighbour’s nest for them to rear. This makes me wonder if this is part of the evolutionary process by which birds like the cuckoo learned to give up nest-building and chick-rearing altogether.
During the next few days, the chicks follow hard on the heels of their parents, or wait impatiently on a tree branch for food to arrive. I’ve noticed that they start to peck at anything that looks the slightest bit edible.
I suspect that most birds are ‘hard-wired’ to peck, and so, following the example of their parents, will learn what’s edible and what’s not, just as most young animals, humans included, will pick up anything and put it straight in their mouths.
Some of the fledglings are definitely faster studies than others, not just in this question of feeding themselves, but also in paying attention to the social cues of the other birds. I’ve noticed that some youngsters will head off as soon as a much larger bird lands on the bird table, while others have to be practically knocked off of it. Some stay quiet when there’s a mass scatter of the birds to the safety of the trees, while others carry on calling. I suspect that again you could probably track the process of evolution here – the quicker a youngster is on the uptake, the more likely it is to survive to pass on its genes. There is also some evidence that animals in cities that have a variety of threats and opportunities to contend with become more ‘intelligent’ (by our standards) than country creatures – in fact, animals in any particularly challenging environment may evolve to have a wider range of strategies for survival than those who live where food is plentiful. The article here has a number of interesting examples, from mountain chickadees to raccoons.
Over the next few days, the adult starlings will gradually make their youngsters independent. They will bring less food to them, and take a longer time between visits. They will become more inpatient with infants who follow them, and will sometimes try to escape their demanding offspring. This is a hard period for the fledglings, who will now have to try to fend for themselves – approximately 50 – 80% of all nestlings fledge, but only 20% of these will survive to breed. Everything eats fledgling starlings, from jays, magpies, crows and sparrowhawks to that most dedicated of predators the domestic cat, who takes more fledglings than all other predators put together. At this time of year it’s imperative to bell any outdoor cats, or at least keep them in at dawn and dusk.
The winter will also take its toll – many starlings no longer migrate, especially those in urban areas where there is usually enough food. The fledglings need to learn where to feed, drink and roost now, so that they will be prepared for the colder weather. They offset some of this difficulty by forming into flocks of adolescents, both because many eyes can identify sources of food more quickly, and because the bonds formed now will give them an advantage when they come to breed themselves next year.
The adults will have a brief period of rest and foraging for themselves before they ‘decide’ whether or not to try for a second brood.
I had always thought that the only way of ‘sexing’ adult starlings is by the small patch of colour at the base of the beak, but apparently the irises of the birds are different colours – rich brown in the male, a lighter, more mousey brown in the female. Now all I need is good light and my binoculars handy.
And soon the hubbub will have died down for another year, as the adult birds moult and everything goes quiet in the garden. At the moment, though, I am awoken every morning at 5 a.m by the sound of young starlings looking for their breakfast. I imagine the neighbours are delighted.