Of irruptions and hazy days

12 Nov

For the more experienced (i.e. older) amongst us, cast your mind back to your childhood going on summer days out with your parents. I have vivid recollections of the windscreen getting covered in squashed insects leaving smears and all kinds of marks on the front of the car which my father would spend ages trying to clean off. I also seem to recollect you could buy plastic covers to go over the front of the car to stop the paintwork being damaged… (OK – where is he going with this one..)

The point being is that we simply don’t get the number of insects we used to and, as a consequence, there isn’t as much for food for insectivores (Shrews, Swallows, Blackcaps etc) – so we don’t have as many insect predators as we used to – so we don’t have as many higher level predators such as birds of prey and stoats. (This is what’s known in ecological circles at trophic layers). Given a chance nature can recover quite quickly from population declines but in reality nearly all our countryside is quite heavily managed especially when you compare it to rural France or Poland where there is still lots of messy and unimproved bits as there isn’t as much pressure on farmers.

The more long-term deeper concern is what our children will see a lack of insects as normal.

On a more positive note the autumn bird migration will be almost complete in November with the usual suspects here in good numbers such as Fieldfares and Redwings. Many other continental birds such as Starlings, Jays, Wood Pigeons and Goldfinches will have arrived. In some years the number arriving is quite incredible. For example in November 2010 some 161,000 Wood Pigeons flew over a site in Dorset in 1 day!! (This wasn’t a typo..). In 2014 some 50,000 Swallows also flew over a site in Dorset in 1 day and in 2011 some 10,000 Goldfinches flew over a site in Kent in 1 day.

Sometimes these large numbers are due to the shortage of food for the birds in their summer grounds, or having a couple of successful years breeding when the numbers of individuals can significantly increase. This is known as an Irruption and in some years some unusual birds can arrive here such as 3 years ago when we had lots of Waxwings in the apple tree next to the village school.

If this winter proves to be a cold one and, just having completed a great breeding season for most birds, we may get all sorts of strange immigrants in the village.

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