Why is bird song so intense these days?
This phenomenon is called the “dawn chorus” and is the expression of the formation of couples. From the months of March and April, the bird breeding season is in full swing. And since food reserves, mainly insects and seeds, are not yet at their maximum, males fiercely and assiduously reserve their territory for reproduction, nesting and larder. They therefore sing to preserve their space, repel neighboring males, and to attract females.
They are therefore the most talkative males. Do females sing too?
Only males sing, with a few exceptions. Females respond with a whole vocabulary of social calls.
Do we observe “time slots” for each species?
Yes. It is the blackbird who first begins this concert, in the dark, even before daybreak. It then calms down when the sun arrives. The black redstart and the robin follow him at dawn. Then everyone else joins in the song. Others wait for the heat to rise, like warblers. In reality, the tracks overlap, forming a real sound soup.
In the afternoon, they feed. And at the end of the day, a renewal of song for many species is heard.
What can promote singing?
Beautiful weather! Like us, birds appreciate good weather. Rain, wind, gray weather, they don’t like it! And in urban areas, they sing much earlier, with the presence of street lights.
Does global warming impact this phenomenon?
Yes. The singing period has been advancing for around thirty years, particularly with the hatching of insects which arrives early, also bringing forward the reproduction period, and therefore the singing. We are counting 5 to 10 days in advance. I was surprised to hear cuckoos in early April this year.
This is especially problematic for migratory birds, which bring forward their return date, but less quickly than the effect of global warming. They therefore arrive late for the insects to hatch, which puts them at a disadvantage compared to sedentary birds…
What is the climax of the “dawn chorus”?
It peaks around May 1. Because this is the period when migratory birds have all joined the sedentary passerines. The wave of warblers, chiffchaffs, cuckoos and swallows adds a layer of song to the opera!
It is also the time when flowers and leaves bloom, giving the most magical spectacle of the year for a naturalist.
In June, certain species sing loudly again, like the titmouse, hoping to find a second female for another brood.
And at the end of June, the songs will die out when the little ones have been raised, and there will be no more challenges for food. Stocks of insects and seeds will be at their maximum in summer. No need to defend an area tooth and nail. Then the forests and meadows will become silent again in July.
Discoveries this May 1st
This Wednesday, May 1st, no lie-ins for music lovers curious about bird songs! It’s the “Dawn of the Birds”. At first light in the morning, dozens of nature guides arrange to meet little feathered singers at around thirty sites in Wallonia and Brussels.
Like a musicologist playing a particular instrument in an orchestra, the passionate guides help identify each trill of each species. Many walks are preceded by presentations or conferences on various themes. As in Gouy-lez-Piéton, where guide Alain Paquet presents the birds of the agricultural plains and their decline, recalling the Silent Spring alert (1962) by Rachel Carson, one of the first ecological works decrying the damage of pesticides.
And the guide reminds us of the pleasure of observing birds. “It’s a group of extremely accessible living beings. We are perhaps closer to mammals. But we don’t see them! On the other hand, when we look in the garden, the birds can be seen everywhere and are noisy! They are diurnal like us, use the same sensory channels as us: the eye and the ear, and little sense of smell… We are closer to them than we imagine.” The event is held once every three years. Equip yourself with a pair of binoculars. Registration sometimes required.
Programme: www.natagora.be/aube
