It's time to return my regular weekly series of blogs highlighting some of the 70 species to spot at Minsmere. Since launching this checklist last spring I've focused on most of the species listed, as well as a couple of additional ones, and this week i turn the spotlight on something a little different the knopper gall.
First, before anyone starts to correct me, I need to come clean, as technically knopper gall is not actually a species in itself. As with all galls, it has developed as a result of an insect laying its eggs in part of a plant, leading to an abnormal growth. In this instance the species is a tiny wasp, and it has a very interesting life cycle.
The wasp, Andricus quercuscalicis, has a two year life cycle that requires two different species of oak tree for completion. First the eggs are laid in the male catkins of the Turkey oak - a non-native species that is widely planted in the UK and is common here at Minsmere. The second generation develops in the seed bud of the native pedunculate oak (often known as English oak, or just oak). Instead of this bud developing into an acorn, it becomes a knopper gall.
A knopper gall (photo via Wikimedia Commons)
Knopper galls are very distinctive, with their ridged shape. They can often be found growing on the oak trees around the visitor centre and North Bushes, but are more easily seen once they fall to the ground and litter the paths. They are certainly quite obvious at the moment.
Whilst checking the trees around the North Bushes, don't forget to look for the many birds that are refueling on their long journey south. You may find lesser whitethroats, common whitethroats, blackcaps or chiffchaffs feeding on ripe blackberries or various insects. There will probably be several robins in attendance - these might well be freshly arrived from Scandinavia. Yesterday I found a spotted flycatcher doing what it says on the can and catching flies, while today I watched a lovely family of bullfinches in these bushes. The Waveney Bird Club will be here again on Thursday for another ringing demonstration so they may catch a few of these birds to show you. After that, we plan to re-open the winter trail through the North Bushes.
Spotted flycatcher by Jon Evans
Perhaps the most unexpected migrant so far this week was a very late juvenile cuckoo that flew past Bittern Hide yesterday. Look out over the reedbeds, too, for hobbies hawking dragonflies, marsh harriers, or perhaps one of the great white egrets that remains. The latter are most often seen from Bittern Hide, or behind Wildlife Lookout, but do also visit North Marsh and Island Mere. A red kite floew over today, too. Another very welcome species this week has been Cetti's warbler, with reports of birds singing near both Wildlife Lookout and Island Mere. Hopefully this may signal an upturn in their fortunes after being almost wiped out at Minsmere by February's Beast from the East.
For birdwatchers, the main attention has again been on the Scrape, with various species coming, going or simply passing through. Most notable has been the annual late summer departure of our avocets which have moved to either local estuaries or those of the South West. Only two remained today, so we'll have to wait until March for any more flocks of these elegant waders. The terns, too, have departed, with just a couple of juvenile common and Sandwich terns seen today. Likewise there are only a handful of little gulls here now, but a second Mediterranean gull was on West Scrape today.
There is, however, a good selection of waders still passing through. Numbers and variety change every day, but today they included two little stints, 12 dunlins, five ruff, three green and one common sandpiper, one curlew, 15+ snipe, 25+ black-tailed godwits and at least ten ringed plovers.
Little stint by Jon Evans
Duck numbers continue to increase, with a notable arrival of wigeons to join the teals, gadwalls, mallards and shovelers. A female pintail and a female scaup are probably the pick of the ducks, but can be hard to spot if they're sleeping on the islands. there's also moulting flocks of greylag, Canada and barnacle geese, while two velvet scoters were found among a flock of 50 common scoters offshore today.
There's also lots of insects still active, including willow emerald damselflies near Wildlife Lookout, grayling butterflies along the dunes, great green bush-crickets in any grassy areas and hornet mimic hoverflies on the buddleia bushes. Several wasp spiders can be found by looking carefully in the long grass along the dunes. Both adder and slow worm were seen yesterday and up to four water voles can be seen around the pond.
Great green bush-cricket by Jon Evans