Winter survival in wrens
by Lewis, 16 December, 2016, 2 comments
The wren is a small, brown bird; it has an almost rounded outline. It is a somewhat 'dumpy bird', with a fine bill and relatively long legs, and short, 'round' wings. Its tail is short and often held high - (though not in the picture here!). Like many small birds and mammals - it suffers in very cold winters. Researchers at the University of East Anglia have found evidence that wren populations may be adapted to local climates. Using data from the Breeding Bird Survey (run by the BTO, RSPB and JNCC), they found that wren populations were susceptible to harsh winter weather (as measured by the number of days with ground frost) BUT that northern (Scottish) populations were more resilient to harsh winters, even though these birds sometimes experienced 70% more frost days than their southern counterparts. Information collected by bird ringers indicated that the body weight of the wrens in the warmest area (the south west) was 5% lower than those in coldest area (East Scotland). Read more...
