There are signs of summer aplenty, with two chiffchaffs singing on the 17th, two reed buntings (not a long-distance migrant, but only a summer visitor to Hambrook) on the 1st , and no fewer than four great crested grebes on Tonford Lake on 23rd, although it probably isn’t big enough to support two pairs of this elegant waterbird. And talking of elegance, I mustn’t omit mention of eight wonderful little egrets around the edge of that lake the same morning. A pair of mandarin ducks (pictured) were present on the river on the 4th, and two flew up the valley a fortnight later, so it looks as though we’ll have a breeding pair again along this stretch of the river.

Spring is a time of flux, and some sightings refer to birds that are just passing through. Into this category falls the pair of gadwall (right) seen by a visitor on 26th . Small numbers of these attractive, if rather subdued ducks overwinter on the string of old gravel pits further upriver, but come spring they move away to nest on the North Kent marshes and Thanet. Meanwhile, up to 18 tufted duck were still present on neighbouring Tonford Lake at the month end; they have a more widespread breeding distribution across Kent, and most will be dispersing shortly, though the odd pair or two sometimes nests locally.

Another record of birds on passage was the group of five Mediterranean gulls flying over on the 8th. This is a relatively recent colonist of the UK, but is now well-established as a breeding bird on the North Kent Marshes. In winter, birds may wander far inland to feed, so it was surprising that this was my first record of the bird for Hambrook Marshes, and the 102nd species on my list. It is a rather splendid bird which, unlike the so-called black-headed gull, has a hood that really is jet-black, setting off a white eye-ring and bright red bill to perfection and matching red legs. Its distinctive call reminds me of a cat’s miaow, not so unlike one of the calls of the much more familiar herring gull.

Other birds of interest included eleven collared doves flying over on the 1st; 13 crows congregating in the tall poplars on the old railway embankment on the 8th; two mute swans on the river on the 17th; and two buzzards overhead on 23rd. A warm day in early spring is a good time to look out for these raptors, as they take advantage of thermals to spiral high up into the sky for a mixture of courtship display to attract a mate and marking out a territory to discourage wandering buzzards from thinking of setting up home locally.

Another welcome sign of spring was the appearance of flowering snake’s-head fritillaries. I was only able to locate one from the original planting scheme in the boardwalk field in 2010, but 26 of the bulbs planted in the hay field last autumn put on a delicate display of their lantern-like flowers, and careful searching revealed the presence of at least a further 36 non-flowering plants – as the leaves are remarkably grass-like, these “blind” plants were remarkably hard to spot, and there could well have been more. All this was despite the fact that many of the bulbs remained waterlogged throughout last winter’s exceptionally wet weather. If more are planted this autumn it will be worth trying to locate them on slightly higher ground because, although they like damp conditions, they are not really adapted to life under water. The common colour is purple with paler chequering (left), which gives the petals a fancied resemblance to the scales on a snake’s head, while ‘fritillary’ is also the name of a group of butterflies that have a similar chequered pattern on their wings. Quite a sizeable minority of fritillary flowers are white or even pinkish; these are natural variations that occur in wild populations.