We know why bird song is a feature of Spring – it’s because the function of bird song is usually to defend a territory and its food and nesting resources and to attract a mate. Song is largely concentrated in the Spring in high latitudes because that’s when birds breed.
But why is there a daily concentration of song around dawn? Why isn’t there a mid-morning chorus or a tea-time chorus?
Today, here in east Northants at 0515 it’s raining – the first for a while. But opening my front door there are still Blackbirds singing away in the dark. It’s obviously quite important to sing at this time of day.
Here are some potential explanations for why most UK songbirds do sing a lot in the time around dawn on these Spring days – the suggestions are not mutually exclusive so all might be partially true;
- the air is cooler and stiller at dawn and this aids the transmission of sound. Turbulent disturbed air leads to degradation of sound quality so dawn is the best time to get your message across
- there’s nothing else to do! It’s dark and so most birds can’t feed, or gather nesting material, so why not use this otherwise rather useless time to sing?
- it’s been dark for 10 hours, and 10 hours is a long time in the life of a small bird. Some will have died overnight and so this is the time to signal that you are alive to your neighbours and potential mates. If the guy next door isn’t singing it’s an opportunity to annex a bit more territory.
- singing draws attention to yourself, that’s what it’s for, but at dawn there are fewer avian predators active perhaps, and so this is a safer time than others in which to sit out in the openm and shout to the world.
- it’s like an early morning exercise routine – it gets you warmed up for the rest of the day.
Any other ideas?