What's Happening in September?

September quickens the heart of many a naturalist as countless numbers of migrant birds fly south through Dorset on their way to their winter quarters.

Although each year brings new facts and understanding about bird migration, there are still many mysteries. For example, swallows fly all the way to South Africa, but it is still unclear where house martins overwinter in Africa.

Migrants in the Undergrowth

When you take a walk this month spend time searching for migrants. Look for feeding blackcaps and whitethroats in elder berry bushes, families of spotted flycatchers using open perches to catch flies, redstarts on fence posts and in hedges, wheatears on coastal paths and the numerous waders and song birds in wetland areas. 

Watch Out for Osprey

September is also the best month to see a migrating osprey in Dorset. With over 200 pairs now breeding in Scotland alone, fishing lakes and coastal harbours provide ideal locations for refuelling prior to the channel crossing and the onward flight to West Africa.

Scan large dead trees in suitable locations and watch for panic amongst waders and gulls if a large somewhat gull-like bird of prey flies into view. You may be rewarded with the sight of an osprey hovering prior to plunging into the water and catching a fish!

The Horders

Meanwhile, our resident birds are actively preparing for winter. The jay, with its greyish-pink body, white rump and azure-blue wing patch is very conspicuous as it flies to an oak tree, collects a few acorns then caches them underground as winter food. It has been estimated that each jay stores around 5000 acorns each autumn, not all of which are remembered, thus helping to maintain our oak woodlands.

Love them or loathe them, grey squirrel numbers peak in the autumn after having litters in both spring and summer. Hazel nuts, acorns, beech mast and sweet chestnuts are all exploited and some are stored underground, in tree hollows or in their dreys for use in the winter. 

Butterflies on the Brambles

If you go blackberry picking in the hedgerows this month, you may encounter the comma butterfly. The scalloped wings and cryptic markings on the undersides of the wings provide perfect camouflage for hibernation over winter.
In addition, the small tortoiseshell which has been very scarce for the past two years has now reappeared in numbers and two generations through the summer may help to re-establish this widespread and familiar species.

Basking in the Late Summer Sun

September often provides warm settled conditions in which lizards can feed on small invertebrates and grow before hibernating. The ubiquitous common lizard produces live young around July which grow to about 3 inches before hibernating. Look for them basking on logs and in the margins of paths near good cover.

In contrast, the sand lizard, a larger species with a severely restricted distribution in Britain, lays eggs in bare sand in June/July. After hatching in August the young feed well and also reach about 3 inches before hibernating.

Gentian Delight

Finally, that spectacular plant, the marsh gentian flowers on wet heaths in the Poole basin this month. The large deep-blue flowers are trumpet-shaped and point skywards. Some small plants have just one flower, but more substantial plants can have six or more flowers and live for over 20 years.

Written by John Wright
Dorset Wildlife Trust Member & Volunteer

Blackcap

Comma Butterfly

Sand Lizard

Marsh Gentian

Photographs by John Wright