The science behind soaring, how birds keep cool, reedbed life, Common Crossbills and egret species are all covered this month.
WHILE July might not be the best month for vismig, this doesn’t mean you should take your eye off the sky.
With warmer weather, conditions are often perfect for looking for soaring raptors. A hot morning brings thermals, rising columns of warm air, which a bird with a large wingspan can take advantage of. By riding this column, a raptor can effortlessly be carried up high, where it can then glide for some distance, without flapping. Gaining height also enables prey or other food to be seen more easily. One of the reasons why birds soaring in a thermal tend to circle is that by using a spiral pattern of ascent, they are more likely to encounter the next updraught, while flying in a straight line or on a random path tends to lead to a gradual drop in height.
It takes time for the air to heat up so mid-morning to midafternoon is the best time to watch for soaring birds. To see them well, a high vantage point is required, with good visibility across woodland and open countryside, so try to find the top of a hill. Watch for large birds like Common Buzzard or Red Kite or even Raven, as they will stand out, and having located one, you might find smaller birds such as Eurasian Sparrowhawk, Common Kestrel or Eurasian Hobby using the same thermals.
Even at a distance it is possible to distinguish between soaring birds of prey. Look for wing and tail shape, as well as tail length. How are the wings held, flat or in a shallow ‘V’?
Look for any contrasts of light and dark. Remember that shapes can change depending on what the bird is doing. A soaring bird will have wings and tail spread as much as possible to catch the updraught, but if it decides to travel away, then its wings may narrow and tail may close so it can pick up speed.
Chris Harbard