NIAB - National Institute of Agricultural Botany

Orson's Oracle

A noisy summer

Posted on 02/09/2013 by Jim Orson

We live very close to the centre of Cambridge. Despite that, it’s a normally a quiet area but this summer has been different. The garden has been exceptionally noisy with bees buzzing and butterfly wings flapping.

The only thing missing is bird song. Despite the best efforts of the neighbourhood to feed them, small birds have all but disappeared and those that do appear skulk in the bushes hoping that they will not be seen by the local sparrow hawks. One bird that has completely disappeared from our garden is the magpie. We’ve had high numbers in the previous couple of years when I assume that they hoovered up the nests of small birds and so having exhausted the local territory they have now moved on. The only birds we now see and hear regularly are pigeons although a green woodpecker makes an occasional visit.

The increased number of bees and butterflies could perhaps have been predicted. I’d noticed that the cool and consequently ‘long’ spring resulted in a relatively constant high number of flowers in hedgerows and field edges.  

The relatively high numbers at any one time were possibly due to two factors. Firstly the flowering period of each plant lasted a bit longer in the cool conditions. And secondly the constancy of the supply of flowers may have been due to the fact that in a cool spring the flowering periods of different plants were more likely to overlap rather than occur closely together. This may be because the time of flowering of some species is more determined by day length and in other species by accumulated temperature.

So in a warm spring the flowering of some species may be brought forward to a time when other plant species whose development is more determined by day length are also flowering. I must admit that this is pure conjecture based on observation and that this year’s dry spring might also have contributed to higher numbers of some species.

To take this conjecture to a further stage, are the reported warmer springs, compared to previous decades, contributing to a decline in biodiversity? It is perhaps an issue that is worth investigating. Please do not take this as an answer for all the decline in biodiversity on arable land but it may be that it should be explored as a contributory factor.

There is a lot of debate in the national press about the decline of one ‘cuddly’ garden species. Whilst I realise that you really cannot cuddle a hedgehog, they are a very popular animal. The Sunday times devoted a whole page to their decline and the usual suspects were mentioned, land change and pesticides. What was not mentioned was the fact that their main predator is the badger, whose numbers are flourishing. Surely there is a connection here but badgers were not mentioned once. My allotment is in a semi-urban environment and yet when it is dry there are signs of badger activity, suggesting that they are a less shy species than I had presumed.

The Sunday Times article reflects much of the press output on other ‘cuddly’ species. Everything but natural predators are mentioned along with an anti-food production message. In the natural world there are inconvenient truths but pressure groups do not mention them possibly because they may upset other pressure groups and/or they may upset their subscribers. So they retreat into a rather surreal world where there is a common enemy on which they can all agree. Perhaps this is a core reason why some consumers have totally unrealistic fears about pesticides and pesticide use.

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