Small birds fly at high altitudes towards Africa

Date:  August 6, 2018

Source:  Lund University

A new study from Lund University in Sweden shows that small birds migrating from Scandinavia to Africa in the autumn occasionally fly as high as 4,000 metres above sea level -- probably adjusting their flight to take advantage of favourable winds and different wind layers.

This is the first time that researchers have tracked how high small birds fly all the way from Sweden to Africa. Previous studies have successfully logged the flight height of larger migratory birds.

"We only followed two individuals and two species. But the fact that both of them flew so high does surprise me. It's fascinating and it raises new questions about the physiology of birds. How do they cope with the air pressure, thin air and low temperatures at these heights?," says Sissel Sjöberg, biologist at Lund University and the Zoological Museum in Copenhagen.

The aim of the study was to investigate whether the measuring method itself works on small birds, that is, to measure acceleration, barometric pressure (air pressure) and temperature throughout the flight using a small data logger attached to the bird.

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Small birds almost overheat while feeding their young

Date:  May 16, 2018

Source:  Lund University

For decades, researchers have thought that access to food determined the brood size of birds. Now, biologists at Lund University in Sweden have discovered a completely new explanation: the body temperature of small birds can increase by more than 4°C to exceed 45°C when they are feeding their young. Larger broods would require more work, resulting in even higher body temperatures -- something the birds would probably not survive.

"A body temperature of over 45°C must be close to fatal even for small birds," says Jan-Åke Nilsson, professor at Lund University.

Small birds, passerines, normally have a body temperature of around 41°C. Jan-Åke Nilsson and his colleague Andreas Nord studied marsh tits, discovering that their body temperature increased considerably as they worked hard, for example when feeding their young.

Flying back and forth to the nest means they do not get the opportunity to get rid of excess heat, resulting in a higher body temperature.

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Small birds have more efficient wing strokes than bats

Date:  February 5, 2018

Source:  Lund University

Summary:

Small birds are more energy-efficient than bats when flying. Researchers previously believed this was due to air resistance created by the bats' ears. However, biologists have now discovered another reason.

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Small birds expected to bounce back in annual UK count

RSPB says successful breeding season and kind weather could see many species faring well in this year’s Big Garden Birdwatch

Patrick Barkham

Fri 26 Jan 2018 06.01 GMT

Blue tits, great tits, greenfinches and chaffinches are set to bounce back into British gardens this winter after a successful breeding season and “relatively kind” conditions.

More than half a million people are expected to spend an hour this weekend spotting birds and other wildlife in the 39th year of the Big Garden Birdwatch, the world’s biggest wildlife survey.

The RSPB is predicting a bumper year for colourful finches and members of the tit family, including long-tailed tits, after disease and wet weather caused a population slump.

“This year could be a bumper weekend of sightings for some of our resident British birds,” said Daniel Hayhow, RSPB conservation scientist. “So keep your eyes peeled for the greenfinches, chaffinches and various tit species.”

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Small birds prefer flying in company

Date:February 1, 2016

Source:Plataforma SINC

Until now, scientists had observed that some large birds are sociable amongst each other. However, a new study has confirmed that this unique characteristic can also be seen among smaller birds such as the Eurasian siskin, a bird which is able to form bonds that last for a number of years as well as travel long distances in the company of these birds. This intimacy may favour reproduction in addition to facilitating the process of adjusting to a new place.

The sociability of swans, geese and birds of the crow family has been studied and is well understood by scientists. These are large birds that tend to form stable, long-lasting bonds. This peculiarity, however, had not been observed in smaller birds, such is the case with the Eurasian siskin (Carduelis spinus). A study published in 'Bird Study' reveals that this species has a tendency to travel long distances in groups over the course of several years. Up to this time, researchers from the Natural Sciences Museum of Barcelona -the leaders of this study- had discovered that female Eurasian siskins in captivity prefer to mate with males that they know. Nevertheless, the investigators still needed to prove that these birds, when out in nature, do indeed live together for periods of time that are long enough for these specimens to interact and to get to know each other.

"In this study we show how the Eurasian siskin is able to form stable group relationships lasting for periods of several years in addition to travelling in each other' company over distances spanning more than 1,000 km," points out Juan Carlos Senar, lead author of this study and a scientist at the museum.

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How do small birds survive cold winters?

Date:

January 27, 2015

Source:

The Norwegian University of Science and Technology (NTNU)

Summary:

Norway's small birds face many challenges during the winter, including short days and long energy-intensive nights, tough weather conditions and food shortages, along with the risk of becoming a meal for hungry predators. 

Many of the smallest birds live on the edge of survival with this enormous physical pressure.

Bottleneck period

Northern winters are the limiting factor for many creatures. This is especially true for the smallest birds, which have to use every daylight minute to find food. They are constantly adjusting to shifts in weather and trying to fend off starvation.

Cold temperatures, strong winds and snow-covered branches increase the stress factors for birds that primarily reside in trees. The birds optimize their energy balance by changing location continuously depending on the weather.

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When David beats Goliath: Smaller birds can dominate larger species, especially when related

Date:
September 24, 2014

Source:
Queen's University

Summary:
Body size has long been recognized to play a key role in shaping species interactions, with larger species usually winning conflicts with their smaller counterparts. But a biologist has now found that occasionally, small species of birds can dominate larger species during aggressive interactions, particularly when they interact with distantly related species.


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Small birds capitalize on weather patterns during epic migrations

Date:

May 6, 2014

Source:

Cornell University

Summary:

In one of the greatest feats of endurance in the biological world, millions of tiny songbirds -- many weighing less than an ounce -- migrate thousands of miles to Central and South America each year. Now scientists are finding out how these featherweights do it: using elliptical routes that take advantage of prevailing wind patterns to save calories.

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