Bird feeding helps females more than males

Date:
June 12, 2020
Source:
Lund University
Summary:
A new study shows that female birds benefit more from extra food
in the winter. If females receive additional food, they do not
need to reduce their body temperature as much as they would have
otherwise, and the chances of surviving cold nights increase.



FULL STORY ==========================================================================
A new study from Lund University in Sweden shows that female birds benefit
more from extra food in the winter. If females receive additional food,
they do not need to reduce their body temperature as much as they would
have otherwise, and the chances of surviving cold nights increase.


========================================================================== Birds possess an extreme ability to regulate their own body
temperature. On cold winter nights, they reduce their body temperature
several degrees to save energy and increase their chances of survival. The disadvantage is that the birds become more lethargic, and there is a
risk of becoming easier prey for predators.

Now, researchers have shown that supplemental winter feeding is good for
great tits, at least for females. The females that had access to extra
food in winter did not reduce their body temperature at night as much
as females who received no supplemental food. Among males, no difference
in their body temperature response was noted.

"We believe it is due to males being dominant, and they manage to secure sufficient food regardless of how much is available. Females, on the
other hand, are subordinate and do not have priority access to food. If
there is only a little food, males have priority and ensure that they
eat enough to maintain a high body temperature," says Johan Nilsson,
biologist at Lund University.

The study was carried out in winter at Vombs Fure, a coniferous forest
outside Lund. In one part of the forest, the researchers put out bird
feeders. In another, the birds received no supplemental food. The
researchers then measured and compared the birds' body temperature
at night.

Johan Nilsson points out that the study was carried out in a forest,
and it is therefore uncertain whether bird feeding in cities is always
good in general.

"What we can say, with certainty, is that females in nature benefit from
being fed in winter," he says.


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


========================================================================== Journal Reference:
1. Johan F. Nilsson, Jan-AAke Nilsson, Juli Broggi, Hannah Watson.

Predictability of food supply modulates nocturnal hypothermia in
a small passerine. Biology Letters, 2020; 16 (6): 20200133 DOI:
10.1098/ rsbl.2020.0133 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200612111348.htm

--- up 20 weeks, 3 days, 2 hours, 34 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)