In the week or so since my last blog, we've been visited by several notable globetrotters of both the avian and human varieties. The latter have included representatives of conservation organisation in Denmark and Indonesia visiting Minsmere to learn more about how we manage the reserve for wildlife and people. I've also had some lovely conversations with birdwatchers from the USA, Canada and South Africa this week.

Of the birds, by far the most outstanding sighting was the huge Caspian tern that was discovered on South Scrape by one of our former wardens last Saturday. Caspian terns are the largest terns in the world - almost matching herring gulls for size - and have equally large bright red bills. Although they have a large global distribution, found in Europe, Asia, Africa, North America and Australasia, they remain rare visitors tot he UK, with just a handful of sightings per year. All recent sightings at Minsmere have involved birds that have made only very brief visits, so many local birdwatchers were pleased when this bird chose to linger. It spent most of Saturday and Sunday on South Scrape, with brief forays to Island Mere to feed, but sadly it had departed by the time I returned from a weekend away on Monday!

Caspian tern by Paul Green

This isn't the only scarce tern to pay a visit to Minsmere this week, with several reports of a roseate tern on South Scrape, too. A bit more careful searching is required to spot this bird, which is distinguished by its very pale plumage and all black bill, with just a hint of red at the base, especially as there are also a couple of second-year common terns present that also sport an all black bill. The roseate tern should stand out from the common terns by the paleness of its upperpart feathers.

Hopefully both of these scarce terns will avoid contracting bird flu, which continues to cause the deaths of some of our other terns and gulls and looks to be a major concern for the conservation of several globally threatened species of seabird. Despite this, we're still seeing good numbers of Mediterranean gulls and Sandwich terns, plus the odd little tern or little gull among the breeding common terns and black-headed gulls.

Mediterranean gulls (centre, with black head, bright red bill and white wing tips) surrounded by black-headed gulls (with chocolate-brown heads) and a common tern

In a similar vein, the breeding avocets, lapwings and oystercatchers have been joined on the Scrape by the first southbound waders, including spotted redshanks, green sandpipers, common sandpipers and ruffs. These are birds that have already been to the Arctic or Scandinavia and have returned south having either failed to breed successfully or left their mates in sole charge of the eggs and young!

There's also been a notable increase in the numbers of teals on the Scrape as they start to return from their northern breeding areas to moult at Minsmere, joining the gadwalls, shovelers, mallards, shelducks and feral geese.

Out in the reedbed, we're still getting regular sighting of bitterns as the females continue to feed their chicks, while many of the marsh harrier chicks are now on the wings and can be seen practicing their flying skills or calling to their parents to feed them. Hobbies have become a bit less reliable, but can often be spotted chasing the nesting sand martins. A kingfisher was spotted from Bittern Hide this morning, but neither the great egrets nor glossy ibises are being reported often now. Bearded tits, Cetti's warblers, reed and sedge warblers and reed buntings are often spotted flitting around the reedbed, but none are singing very often.

There is also a great mix of insects to spot, including most of the usual suspects in Digger Alley: bee-wolves, ornate-tailed wasps, red-banded sand wasps, pantaloon bees, green-eyed flower-bees and ruby-tailed wasps. I've just been watching several female emperor dragonflies laying eggs in the pond, as well as Norfolk hawkers, four-spotted chasers and a variety of damselflies: azure, variable, blue-tailed and emerald.

The first white admiral and purple hairstreak butterflies are now on the wing, and last week's butterfly transect volunteers recorded an incredible 60+ silver-washed fritillaries. Just a few years we were excited to see two or three of these large orange-and-black butterflies.

Purple hairstreak is always a difficult butterfly to spot as they tend to remain high in the oak canopy. Canopy Hide is a good place to try. Photo by Jon Evans