The changeover between seasons often leads to some unpredictable sightings, but when warm spring-like in late February is followed blustery, showery autumnal weather in early March, it's hardly a surprise that the wildlife can get a bit muddled up.

That is certainly the case this week, with reports from our guides reflecting many early signs of spring, mixed in with plenty of lingering winter records. In particular, it's not often that you can see that classic cold-weather visitor from the Arctic, the smew, alongside a trans-Saharan visitor, newly in from Africa, in the shape of a sand martin.

Yes folks, we welcomed back the first two sand martins on the incredibly early date of Friday 1 March, and these two birds continue to be seen hawking for insects over Island Mere and the reedbed in front of Bittern Hide. Sand martins are always one of our first summer migrants to return, having spent the winter farther north than the closely related swallows, but it's very unusual to see the first ones back earlier that St Patrick's Day - 17 March. This year, however, they were in time for St David's Day - and the daffodils came into fill bloom right on cue, too. These two sand martins were just part of a mini influx to the UK this week, but they are only the advance guard and it's likely to be another three weeks before we see the main arrival, along with the first swallows. House martins and swifts, in comparison, are unlikely to arrive before St George's Day - 23 April.

Sand martin by Christine Hall

While 1 March is very early for sand martins (several leading Suffolk birdwatchers reporting them as their earliest ever by about two weeks), it's certainly not early for male adders to be out and about. At least three adders are already active around the Adder Trail, which has now be signposted in the usual area of South Belt, between Bittern Hide and Island Mere. Mornings are the best time to spot them as they bask in a sheltered south-facing spot trying to absorb the sun's rays. They are quite variable in colour, but these are all males, as the females will remain snuggled in their hibernacula (winter dens) until the end of the month.

This male adder was active even on a cloudy afternoon on Saturday

The springlike theme has continued with bitterns booming at Island Mere, marsh harriers sky-dancing over the reedbed and Cetti's warblers shouting their distinctive songs from hidden perches in the reeds, while on the Scrape there are now more than 50 Mediterranean gulls, 30+ avocets, several ringed plovers and oystercatchers and the first redshanks of the year. A male ruff was spotted today too. There are also waders passing through on migration, including dunlins, turnstones, knots and black-tailed godwits.

There's still a wintry theme to the wildlife as well though. The three smew continue to give visitors the runaround as they move between various parts of the Scrape or to the freshwater pools behind North Hide. These pools are best watched from the low mound by the pond. The drake look particularly stunning in the sun, and today our guides witnessed the male mating with one of the females. Such behaviour is unusual in the UK. It doesn't, however, indicate potential breeding, but is simply part of the pair-bond strengthening in advance of their departure to Scandinavia later this month.

Smew by Lesley Hickinbotham

Other lingering winter visitors include a pair of pintails on the Scrape, alongside continuing good numbers of wigeon, gadwall, shoveler, teal, mallard and shelduck. At least two adult whoooper swans remain, and a lone juvenile was still present on Saturday, suggesting that it may have been left behind by it's family. With luck it will manage to return safely to its natal area to breed, whether that's in Scandinavia or Iceland. There's also still a few redwings feeding in the leaf litter in South Belt woods, and one or two lesser redpolls among the flocks of siskins feeding in the alders near the Rhododendron Tunnel.

Lesser redpoll by Jenny Tweedie (rspb-images.com)

Of course, our resident wildlife is also adjusting to the seasons. Dartford warblers and stonechats are establishing territories on the dunes, long-tailed tits are nest-building already, and I even saw a treecreeper carrying nesting material in the Rhododendron Tunnel on Saturday. The woods are now full of birdsong as chaffinches, dunnocks, blue, great, marsh and coal tits, robins, wrens and woodpigeons establish breeding territories. A male reed bunting is also a regular visitor to the feeders outside the visitor centre, as are a pair of great spotted woodpeckers.

Bearded tits are becoming a little easier to locate around the reedbed and reed buntings can be heard singing their rather plaintive song. Otters continue to be seen regularly, mainly at Island Mere or Bittern Hide, though a vocal youngster put on a great show for this morning's guided walk in the pool behind Wildlife Lookout.

Otter by Chris Upson