Less Butterflies, Less Swallows & Martins!

The decline in swallow, martin and swift populations is, among other reasons, related to the decline of the invertebrate populations on which they feed. A report on the state of butterfly populations in the UK was recently published and the results are disheartening: 80% of species are less abundant and their range has shrunk. Although butterflies are not the most common prey for swallows, martins and swifts, this group highlights what is happening to insects across Europe.

In our country, unfortunately we have no data that allows us to say what is happening to butterflies. In Portugal, 2023 will be the fifth year in which a concerted effort is being made to monitor butterflies, with around 80 sites being sampled, thanks to Tagis - Portuguese Butterfly Conservation Centre and all those who have joined in with this initiative. It is a commendable effort, but still insufficient and incomparable with what is done in other countries.

Preserving swallows, martins and swifts must also include preserving the insects on which they feed. For this it is necessary to promote land uses that benefit invertebrates and biodiversity in general and to stop the widespread use of chemicals, especially insecticides!

In-flight baths

Swifts are expert fliers capable of staying in flight for several months without stopping. To achieve this, they need to keep their plumage in excellent condition! It is through feather care, or "preening", that the birds eliminate dust, dirt and parasites, as well as maintain the elasticity, shape and position of their feathers. Like other activities (catching prey, drinking and mating), preening is also carried out by swifts during flight.

These actions are so fast that they go mostly unnoticed even by the most keen observers, and only slow-motion and close-up videos are able to provide an accurate description of these behaviours.

By analysing the videos of the ornithologist Jean-François we realise that by leaning backwards, swifts manage to reach the uropygial gland which secretes an oil rich in waxes, fatty acids and water. This oil is then spread with the beak over the feathers on the back, belly, tail and wings. Head and neck feathers are maintained by the legs: despite having very short legs, swifts are able to slip them under the wing to reach these parts.

Check out some of these movements here!

And the first swallows of the year arrived... last year!

As most swallow species are migratory, the number of swallows seen in Portugal varies greatly throughout the year. There are times when almost all of them are in Africa, and as the migration begins, some pass through Portugal on their way to the north, while others stay here to breed, thus increasing the number of swallows flying in our skies.

Even so, the peak of observations occurs when the birds that reproduced and were born in central and northern Europe join the birds that are here, preparing for another journey south in search of food.

Contrary to common sense and what popular culture tells us, the most difficult time to observe a swallow in Portugal is still in autumn . In the second fortnight of December and even before the beginning of winter, the first swallows of various species that are returning from Africa begin to arrive. And of course, the further south you go, the earlier the observations are!

So, if you see swallows, don't think that the world has turned upside down and that it is the result of climate change. It's normal for them to be around at this time. But beware: this doesn't mean that climate change doesn't affect the swallows' calendar or even their abundance. Not least because one of the factors responsible for their decline is climate change itself. We simply mean that the swallows begin to return from migration, as they always have done, still during winter!

Who has seen any swallows this year?

Good observations to all!