Black swifts descended rapidly during lunar eclipse

Date:
March 17, 2022
Source:
Lund University
Summary:
An international research team has studied the flight behavior
of the mysterious black swift. They found, among other things,
that the black swift rises to extreme heights during a full moon,
seemingly catching insects in the moonlight. And, during a lunar
eclipse, the birds simultaneously lost altitude.



FULL STORY ==========================================================================
An international research team led by Lund University in Sweden has
managed to study the flight behaviour of the mysterious black swift. They found, among other things, that the black swift rises to extreme heights
during a full moon, seemingly catching insects in the moonlight. And,
during a lunar eclipse, the birds simultaneously lost altitude. The
results are published in Current Biology.


==========================================================================
The black swift is a bird species with a bulky body and long, pointed
wings.

The plumage is black with some white areas on its head, and its call is
a series of high-pitched tweets, with the occasional longer squeak. The
black swift is endangered, and has therefore long been of great interest
to the world's bird researchers.

Using microdata loggers and advanced technology, the researchers were
able to map the movement patterns of black swifts during their migration
from the Rocky Mountains in Colorado to the Amazon Basin in Brazil.

"We discovered that the black swift does not land a single time during
their eight and a half month long migration, so they stay in the air
the entire time," says Anders Hedenstro"m, biologist at Lund University.

When the researchers went through the material, they made another
discovery that surprised them. It turned out that the black swifts,
in connection with a full moon, rose to extreme heights at night. While
flying at an altitude of a few hundred meters in daytime, during full
moon nights they rose to between 2000 and 4000 meters.

"The dynamics of the high-altitude flight in relation to the different
phases of the moon came as a total surprise to us," says Anders
Hedenstro"m.

The researchers also managed, by chance, to study the birds in connection
with a lunar eclipse -- when all the birds reacted instantaneously
by diving to much lower altitudes. The moonlight thus has a direct
significance for the black swifts' flight altitude.

"Our results are very exciting, and reminiscent of the vertical movements
in relation to moonlight found in, for example, zooplankton in the
oceans," says Anders Hedenstro"m.


========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
be edited for style and length.


========================================================================== Related Multimedia:
* Black_swift ========================================================================== Journal Reference:
1. Anders Hedenstro"m, Robert A. Sparks, Gabriel Norevik, Colin
Woolley,
Greg J. Levandoski, Susanne AAkesson. Moonlight drives nocturnal
vertical flight dynamics in black swifts. Current Biology, 2022;
DOI: 10.1016/ j.cub.2022.03.006 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220317111903.htm

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