Hobson's heron and the tamer side of Cambridge's wildlife
We continue to bask in the delights of wild nature this month, essential therapy during these stressful and bizarre times. Even as we humans are constrained in our movements and activities, nature rumbles on with the changing seasons.
The morning blackbird serenade begins ever earlier, now starting about 4.30am, with robin, house sparrow, woodpigeons and collared doves joining in a little later.
Usually traffic noise blots out the jolly chirping of house sparrows, but now I hear them clearly in most of our local streets. Reduced traffic noise and cleaner air clearly benefit our urban birds and it is no longer that rare an event to spot buzzards soaring over the city. I spotted three circling above Fenner’s cricket ground recently. Most birds seem tamer too. One heron has taken to stalking the shallow water of Hobson’s Brook to catch sticklebacks just a few yards from passing cyclists and pedestrians, and has become quite a celebrity.
Out in the countryside the hedgerows are bursting out with bright white clusters of hawthorn flowers. Hawthorn, aptly also known as may, is suitably one of this month’s featured species and is most prominent in woods and hedgerows around the city. In some of our local woods lurks one of the country’s prettiest of all wild flowers – the bluebell. We managed a delightful walk into one such wood where ancient oaks, ash and maple towered above a ground flora dominated in parts by carpets of bright, pure blue bluebells. Quite different from those grown in gardens, the wild bluebell flower is a uniform dark purplish-blue while garden forms tend to have larger flowers that are paler and often striped.
Also brightening the tracks and nearby hedges were ground ivy, Jack-by-the-hedge, and white deadnettle, and here and there the strange flowers of wild arum with their cloak-like spathe surrounding a central spadix. This unusual inflorescence is a complex structure evolved to attract insects, notably owl-midges, which are drawn to the warm and smelly spadix which bears the flowers. The female flowers are at the base, with a ring of male flowers above them. In autumn, the female flowers produce bright red poisonous berries.
Another favourite woodland flower of late spring is honeysuckle, whose fragrant spreading flowers are in their prime this month. Butterflies, bumble bees and moths probe honeysuckle flowers for nectar, and many birds feed on the berries in the autumn.
Every May we welcome the return of the swifts which have made the hazardous journey back from Africa. My records go back several years and the swifts nearly always appear during the first week of May, usually around the 4th or 5th, although this year I spotted an early pioneer on April 28, with most arriving as usual during the first week of May. I get the feeling that there are fewer swifts this year but this is based on casual observation rather than careful counting. I hope they will soon start investigating nest-sites under the gutters and eaves of the local houses and entertain us again with their high-pitched screams.