Apr. 15, 2013 —
Researchers believe that the size of birds' nests created in response to
changing weather patterns may be partly to blame for reproductive failures over
the last two years.
An article in the April
edition of The Biologist, the Society of Biology's magazine, explains that
birds produce different sized nests depending on the weather.
Written by Dr Charles
Deeming, senior lecturer at the University of Lincoln
Dr Deeming said: "Over
the past few years scientific interest in nests has increased, with studies
ranging from nest composition, construction behaviour and thermal properties to
the use of nests as potential signals to mates. We've realised that the factors
affecting nest construction are far more complex than we had previously
understood."
Dr Deeming's studies of great
tits and blue tits breeding in nest boxes at the University's Riseholme Park
He found that individual
birds can build extremely different nests each year. Cold weather on the days
the bird was adding lining to the nest meant they built heavier nests than when
the weather was warmer. This suggests that an important function of the nest is
to keep the bird warm while it sits on the eggs. Once the nest is lined, the
female will lay the first egg, which will be incubated for around two weeks.
This means a larger, warmer nest will be important for keeping the bird warm if
the weather is cold.
However, as climate change
brings more unpredictable weather patterns the way birds construct nests will
be affected. In both 2011 and 2012, for example, early spells of warm weather
were followed by much lower temperatures.
At Riseholme, this seems to
have had devastating effects on reproductive success. Birds building in these
early warm periods are likely to construct a light, poorly insulated nest. If
the weather subsequently turns cooler, having a poorly insulated nest may have
an adverse effect on their reproductive success.
Birds use a wide range of
materials in their nests, from moss to sheep's wool, and their availability may
also be altered by climate change. Certain plants may go extinct in local
areas, so some species could lose a key nesting material.
Dr Mark Downs, chief
executive of the Society of Biology, said: "Climate change will have a
large effect on our ecosystems and our food production, and Dr Deeming's is one
of many studies demonstrating that the effects will be complex and difficult to
predict. It is essential that we continue to study how organisms adapt to
climate change and how we can best mitigate its effects."
Dr Deeming concludes:
"Much more research is needed to determine how local climate affects nest
construction. Only then will we start to understand how climate change is
likely to affect nest building, and hence reproductive success."
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