Wing-drying

Such a cold dull,grey day, it's been a struggle to find anything worthy of blipping. The dogs and I went for our usual riverside walk: the willows that blazed orange and red in the late afternoon sun on Sunday were flat and lifeless today.

This time of the year is like that - rapidly changing from warm mild days back to wintry weather. As an ecologist I have a close awareness of the seasons. Although it's artificial to divide the year in any way, as change is gradual and continuous, I recognise six natural seasons. Although average dates for these are given below the actual dates can shift from one year to the next - last year winter definitely started at the end of November!.

Unlocking or prevernal- mid-February to mid-April - early bulbs flowering, many mosses producing sporophytes, birds starting to nest, but fickle weather with a high likelihood of frosts and snow, interspersed with odd milder days.

Spring or vernal - mid-April to mid-June - woodland flowers at their best, sheets of bluebells and ramsons, summer migrants arrived, the dawn chorus, birds nesting and hatching young, early butterflies such as grizzled skipper and green hairstreak, big variety at the moth trap including hawk moths, increasingly warm weather but often with chilly nights.

Summer or estival - mid June to mid August - the peak for grassland flowers, dragonflies, birds fledging their young, lots of hoverflies, periods of hot weather with thunderstorms.

Indian summer or serotinal - mid-August to mid-October - berries ripening, flushes of fungi, peak of garden spider activity, lots of yellow underwings in the moth trap, mostly mild weather with occasional misty days.

Autumnal - mid-October to mid-December - fieldfares and redwings arriving, starling murmurations, more fungi, leaves changing colour and falling, cooler weather with the first frosts of the season.

Winter or hibernal - mid-December to mid-February - flocks of wintering ducks and waders, periods of intense cold with snow and frost.

Anyway, this is all a bit of a diversion because it's not been a very interesting day. These cormorants were probably the highlight of my walk. There's been a small population along the River Nene for many years. Most of them roost in a large willow at Ferry Meadows, but a small group seem to like this pylon. The upper bird has the characteristic 'wing-drying' posture. The structure of cormorant feathers decreases buoyancy and thus facilitates underwater pursuit of fishes. Hence their plumage is not water-repellent, but "wettable" and needs to be allowed to dry after fishing expeditions.