Firstly, apologies for my tardiness in writing this week's species of the week blog. I know that you are used to these appearing on a Monday, and it's Friday today, so I haven't given you much chance to see this week's star species, but don't worry as I've chosen one that will become increasingly obvious as March turns into April.

In fact, this week's star species has actually only just arrived on the reserve, as the first chiffchaffs of spring were heard around the Rhododendron Tunnel this morning. Of all our summer songbirds, this is perhaps the easiest song to learn, along with the equally onomatopoeic cuckoo - the first of which will still be several weeks away. The disyllabic "chiff-chaff chiff-chaff" song will become a familiar sound throughout the spring, and is always  a precursor to the arrival of other spring migrants. What's more, March is a good time to see them singing, often in willow or birch trees, before the leaves unfurl and the birds themselves disappear into the canopy. Look for a tiny olive-green warbler with short pale supercilium (eyebrow), short wings, and dark legs. When the very similarly plumaged willow warblers arrive they have longer wings, paler legs, a more obvious supercilium, and, of course, a very different song.

Chiffchaff by John Bridges (rspb-images.com)

Although chiffchaffs are always thought of as one of the first spring migrants migrants to arrive, they were beaten to that honour this year by a solitary sand martin that was seen hawking for early insects over Island Mere on Wednesday, and again yesterday. This was part of a mini invasion of sand martins into the UK this week, along with several wheatears, the odd swallow, and even a few ospreys - though we're waiting for all of those to arrive at Minsmere.

There was no sign of the sand martin today, but two other typically early spring migrants have arrived: a female black redstart was feeding along the northern edge of the car park this afternoon (with a male near the sluice, and three at nearby Dunwich Heath National Trust reserve), and a gorgeous drake garganey was seen briefly on East Scrape, before flying towards the Scrape. 

  

Today's female black redstart by Ian Barthorpe (note the sooty-brown plumage and orange-red tail that gives it's name)

Of course, while the aforementioned species are generally referred to as spring migrants, for us the first signs of spring are always noted in mid February when the first oystercatchers and ringed plovers return tot he Scrape, followed by returning avocets, black-headed and Mediterranean gulls. Numbers are continuing to increase, and they've been joined by a male ruff, with two grey plovers and the first bar-tailed godwit of the year passing thorough this week too.

Bitterns have been booming for a couple of weeks now, but I finally heard one for the first time this year on my lunchtime walk to Island Mere today. It was a joy to sit in the hide listening to a skylark singing high above the reeds, with bitterns booming, bearded tits pinging and a water rail squealing as marsh harriers called and sky-danced overhead. They weren't the only birds displaying wither, as I watched a buzzard spiraling high into the sky only to plummet towards the ground, before banking up and cruising down into a nearby field to search for earthworms.

Adders are continuing to be reported most days, and butterflies are beginning to emerge from hibernation, with sightings of both peacock and brimstone around the Adder Trail - Rhododendron Tunnel area today. I saw my first bumblebee of the year in the car park today too. Quite what they'll make of the expected drop in temperature this weekend I'm not sure, but once temperatures rise again next week all of these species are sure to become easier to find.

Peacock butterfly by Ian Barthorpe

The forecast mini cold snap should ensure that the family of five whooper swans and the two redhead smew remain for at least a few more days. Another long-stayer is the glossy ibis which is still feeding on the flooded fields at Eastbridge. We still had 40 000 starlings roosting at dusk on Wednesday night, so they too should stay for a little longer yet. they are best seen from the North Wall from 5.30 pm onwards.

Finally, if you are visiting this weekend, please bring wellies or good walking boots. The path from South Belt Crossroads to the Wildlife Lookout and South Hide is wet in places, but passable, as is the entrance to Island Mere. From South Hide to the Sluice, the path is only accessible with wellies, although water levels have begun to drop.

Chiffchaffs may be easy to identify by song, but if you want help with learning birdsong this spring then why not join our volunteers on their Sounds of Spring guided walks during April and May - http://ww2.rspb.org.uk/reserves-and-events/events-dates-and-inspiration/events/details.aspx?id=tcm:9-452134. We even include a light breakfast. For details of other guided walks and family events this spring, and how to book, please see http://ww2.rspb.org.uk/reserves-and-events/find-a-reserve/reserves-a-z/events.aspx?reserve=Minsmere