Night bird hunter

2007/02/19 Rementeria Argote, Nagore - Elhuyar Zientziaren Komunikazioa

• Biologia
• Zoologia

European bats are generally insectivorous. Therefore, it has been discussed about the great nocturnal bat (Nyctalus lasiopterus), since in 2001 researchers of the Doñana Natural Park declared that it also hunted birds. Beliefs asked for more evidence and now have been published evidence that seems to agree.

In 2001 the researchers of Doñana, headed by Carlos Ibáñez, published that they found feathers in the excrements of the great bat of night, even a copy with feathers in the mouth. It is a sign that hunts the passing birds of the great night bats: in the migratory period, autumn-spring, it was believed that it hunted not only insects but also birds.

This practice is not usual and requires a lot of ability to fly. For this reason, other experts, such as the Swiss Arlettaz, were believers. Therefore, in Doñana they continued to seek further evidence and Arlettaz himself met them.

Blood tests were used to learn about the bat diet. According to the diet, the proportion of carbon isotopes in the blood is different from that of nitrogen isotopes. Thanks to this, they knew that in spring the bat eats birds, only insects in summer, and in autumn, more than in spring, birds. These results coincide with the passing time of the birds that pass in spring and autumn. The winter survivors pass through Doñana in spring and in autumn in larger quantities, with young.

Therefore, now the doubts have been resolved and all the experts agree: the bat of night is also bird hunter.

Photo: Ana Popa-Lisseanu.