Noticias Noticias

Why do kestrels soar?

Individuals allocate considerable amounts of energy to movement, which ultimately affects their ability to survive and reproduce. Birds fly by flapping their wings, which is dependent on the chemical energy produced by muscle work, or use soaring-gliding flight, in which chemical energy is replaced with energy harvested from moving air masses, such as thermals. Flapping flight requires more energy than soaring-gliding flight, and this difference in the use of energy increases with body mass. However, soaring-gliding results in lower speeds than flapping, especially for small species. Birds therefore face a trade-off between energy and time costs when deciding which flight strategy to use. Raptors are a group of large birds that typically soar. As relatively light weight raptors, falcons can either soar on weak thermals or fly by flapping with low energy costs. In this paper, we study the flight behavior of the insectivorous lesser kestrel (Falco naumanni) during foraging trips and the influence of solar radiation, which we have adopted as a proxy for thermal formation, on kestrel flight variables. We tracked 35 individuals from two colonies using high frequency GPS-dataloggers over four consecutive breeding seasons. Contrary to expectations, kestrels relied heavily on thermal soaring when foraging, especially during periods of high solar radiation. This produced a circadian pattern in the kestrel flight strategy that led to a spatial segregation of foraging areas. Kestrels flapped towards foraging areas close to the colony when thermals were not available. However, as soon as thermals were formed, they soared on them towards foraging areas far from the colony, especially when they were surrounded by poor foraging habitats. This reduced the chick provisioning rate at the colony. Given that lesser kestrels have a preference for feeding on large insects, and considering the average distance they cover to capture them during foraging trips, to commute using flapping flight would result in a negative energy balance for the family group. Our results show that lesser kestrels prioritize saving energy when foraging, suggesting that kestrels are more energy than time-constrained during the breeding season. informacion[at]ebd.csic.es Hernández-Pliego et al (2015) Why Do Kestrels Soar? PLoS ONE DOI: 10.1371/journal.pone.0145402

 


http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145402
Promedio (0 Votos)

Últimas noticias Últimas noticias

La hormiga argentina perjudica a los polluelos del carbonero común

Las consecuencias de las invasiones de hormigas en los ecosistemas sólo pueden hacerse evidentes después de largos períodos. Además, predecir cómo responderá la fauna nativa sensible sólo es...

Se identifican dos nuevas especies de ardillas de Sonda (Borneo)

Un estudio confirma la existencia de dos nuevas especies de ardillas, que anteriormente eran consideradas subespecies, y de varios linajes genéticos que podrían representar nuevas especies en...

El caballo de las Retuertas de Doñana

Con una población aproximada de 300 ejemplares, el Caballo de las Retuertas se localiza principalmente en el Espacio Natural de Doñana, concretamente en la Reserva Biológica de Doñana y en la...

La estrategia que adopta la sabina mora para tolerar sequías difiere según el sitio

Los episodios de mortalidad de vegetación inducidos por eventos extremos de sequía en ecosistemas forestales están siendo ampliamente estudiados, pero no así en las formaciones arbustivas o...