Nature Notes – August 2017

Early in August, our Swifts will be leaving. They are such a feature of our summer, screaming along the street and around the White Horse, and things seem quieter without them. Until now, studies based on bird ringing could tell us very little about their travels, as so few swift rings are ever recovered. We knew that they travelled into Africa, across the Sahara to winter in Central Africa, but not much more. They seem to travel fast – one young bird was found in Mali by August 1st. With modern methods of satellite tracking a lot more will be learnt about their winter movements. Watch this space.

More broods of young birds we have been seeing in the garden include some Blackcaps. As usual, the young are a duller version of their parents, but in this case with caps that are a dull brown like the female, and not black as in the male. They were feeding, unusually (I can find no other record of this), by pecking at the small wild plums. More typically they were eating the berries of Honeysuckle. Although they are mainly insect feeders, Blackcaps and other warblers often eat sugar-rich berries in early autumn to boost the body fat they will need as reserves on their forthcoming migration. Very important for this is the crop of Elder berries, just the right size, on which they are often to be seen feeding in August.

Despite dry spells, a few July downpours have kept the pond topped up, so the dragonflies, one of my staple summer subjects, are showing well. Two of the Hawkers, large dragonflies with blue and green spots down their bodies, are appearing. These are the Migrant Hawker, whose name tells you much about it although a few do now breed here (I have just been watching a female laying her eggs in the pond), and the Southern Hawker. This latter is much less shy than the others, and will often hover within a couple of feet to investigate a watcher. It is a strange sensation being eyeballed by the huge eyes of such a large insect.

Other insects in evidence in July, and perhaps into August if we have warm, humid days, are flying ants. At home, these were the common Black Ant. In the right weather conditions colonies of these ants produce huge numbers of individuals with wings, both very large females, and smaller (but still bigger than the wingless workers) males. These swarm high into the air to mate. The weather conditions co-ordinate swarming by many colonies from a large area, giving more opportunity for cross mating. Having mated, the females return to the ground, bite off their own wings, and become fertile queens each ready to find a new colony. A cameraman at Wimbledon picked up one of these on Centre Court. The males, of course, are then expendable (insert your own comment here). One sign of these swarms is numbers of birds, usually starlings or as in this case Black-headed Gulls, circling around feeding on the rising column of ants.

This summer the wet ditches of fields and roadsides in the higher parts of our district have been spectacular with the large pink Great Willowherb, going over now but still colourful.

Geoffrey Abbott