Rafts, Birds and Bees

It’s that time of year again, the tern rafts are going out and the migrant waders are on the move. On Tuesday the volunteers got two rafts out onto Ivy Lake, after wintering on the shore.

preparing tern raft for launch

Adding nesting substrate to the raft.

They were occupied by common tern within minutes, although black-headed gull also arrived in numbers and by the end of the day were the only species present. This highlights one of the big problems that terns have these days, as their nesting habitats reduce they are competing more and more with gulls and usually lose out to them.

tern raft with terns (and gulls)

two terns and two gulls on newly floated raft

Yesterday’s migrant birds were mainly waders heading to the high Arctic and included a common sandpiper, a bar-tailed godwit,

bar-tailed godwit

bar-tailed godwit

a very smart turnstone and two dunlin.

dunlin

one of two dunlin

The waders that nest with us are all displaying but none seem to have really settled down yet. Little ringed plover are especially in evidence near Tern Hide.

little ringed plover

Little ringed plover, male

Although it has got cooler the spring insects are still in evidence and some of the earlier season species are beginning to disappear for another year. One such is the rare grey-backed mining bee Andrena vaga, there are only a few females to be found now, but as they feed on willow pollen their food will soon run out.

Andrena vaga

grey-backed mining bee female, one of only a few still flying

If you look at a solitary bee nesting bank there are usually lots of, what at first, look like wasps, but these are actually parasitic bees. Many are very specific as to their host species, I came across two species yesterday. I found what I think was Lathbury’s nomad bee, which uses grey-backed and  the commoner ashy mining bee as hosts.

Nomada lathburiana

Lathbury’s nomad bee Nomada lathburiana

 

I also found lots of painted nomad bee, which visits the nests of the common yellow-legged mining bee.

Nomada fucata

painted nomad bee Nomada fucata

Work continues on the parking area close to the Education Centre, which means that it will not be available for parking until after the weekend, please take note of any signs to keep safe on your visit whilst we have machinery working on site.

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Bee is for Blashford

Or maybe Blashford is for bees, well of course it is! Blashford is for all wildlife and the people who like to experience it. Everyone knows the honey bee and bumble bees, although perhaps not that there are 28 species of them. However there are something like 250 other species of bees in Britain and they all spend their days visiting flowers and pollinating them. These 250 are the so called solitary bees, despite the name they can occur in great aggregations, importantly though each nest is the domain of just one female, there are no worker bees.

Andrena vaga female 2

grey-backed mining bee (female) with a load of willow pollen.

There has been much coverage recently about the declines in insect numbers around the world and that of pollinating insects in particular, perhaps because they are economically important to us as pollinators of crops. Declines could be for many reasons and probably are multi-factored, but a general loss of habitat and an increasing uniformity in what is left, along with increased prevalence of chemical contaminants are all likely contributors. Some enlightened local authorities are modifying their grass mowing regimes on verges, roundabouts and recreation site to allow more flowering, some of the best are actually seeding back wildflowers or using “meadow mixes”. In fact we can all help by providing flowers that are good sources of nectar and by valuing some of the “weeds” that we might have removed in the past. For instance a lawn with dandelions may not win the green-keepers prize but these are a very important source of food for early flying bees and hoverflies.

Blashford Lakes has lots of nectar sources, especially at this time of year when willows are important for many species and so has lots of solitary bees. Many also need bare, sandy soil to dig their nests and we have that in abundance too.

Andrena vaga female emerging from burrow

grey-backed mining bee (female) emerging from nest hole

One of the problems with solitary bees is that some species are very similar to one another and so difficult to identify in the field. Although the grey-backed mining bee female is distinctive the male looks very like the male of another species, the ashy mining bee.

Andrena cineraria male

ashy mining bee (male)

One of the commonest mining bees around at present is the yellow-legged mining bee, which can be found nesting in bare ground in banks, lawns and various other places.

Andrena flavipes male

yellow-legged mining bee (male) – or at least I think it is!

Some bees are neither colonial nor make their own solitary nests, they are nest parasites of other bees. One genus of bees the Nomada bees specialise in this way of life, often specialising on one particular host species. The yellow-legged mining bee plays unwilling host to the painted nomad bee, which looks very wasp-like.

Nomada fucata male

painted nomad bee (male)

The last few of days have seen big arrivals of hirundines, Monday was almost all sand martin, yesterday there were a few swallow and the odd house martin and today there were even more swallow, probably over 50. On Ibsley Water there a couple of pairs of oystercatcher, a pair of redshank, probably five little ringed plover, several lapwing and today two green sandpiper. Meanwhile around the Centre and Woodland Hide the wheezing of brambling is very much in evidence, particularly in the morning, there are at least 30 and I suspect 50 or more around just now.

And remember it does not take much effort not to mow the lawn for a few days and let the dandelions flower to feed the bees. You could put your feet up and have a cup of tea, or a beer (other drinks are available), whilst making your own contribution to Wilding Hampshire!

The Blues

The last few days have seen warm sunshine by day but chilly nights, meaning it has been poor for moths but good for day-flying insects. Today at Blashford Lakes I saw my first scarce chaser and downy emerald of the year and there were other dragonflies about too with reports of emperor, broad-bodied chaser and hairy dragonfly.

Most of the butterflies that over winter by hibernation as adults are getting scarce now and spring species such as orange-tip are dropping in numbers. there are a few whites around with all three of the common species, but the highlight today was the emergence of  blues. The small meadow near Ivy North hide had six or more male common blue as I went to lock up and at least three brown argus as well, the argus is brown, but an honorary “blue” all the same..

common blue male

common blue (male), freshly emerged.

The brown argus look very like small female common blue, and the male common blues will get up to chase one if it flies by, however they quickly realise their mistake and give up. The first emergences are all males and the females will follow in a day or so. The reason for this is the same as that for male migrant bird arriving just ahead of the females. Evolution will push the males to be in place and ready for the first females to arrive, it does not pay to be late, so the pressure for males to be early is greater than that on females, who can afford to wait until they know there will be males to mate with.

The spring solitary bees are starting to disappear now, many species collect pollen from just a few plants and as these cease to flower they need to wrap up their breeding cycle. I did come across one interesting species today though, it was one of the nomad bees and the smallest species of them to be found in Britain, Nomada sheppardana.

Nomada sheppardana

Nomada sheppardana on forget-me-not

Visiting flowers is something many insects have to do to feed, it may sound an unproblematic things to do, the flowers want to offer a nectar reward, or perhaps bribe might be a better description, to the insects that will pollinate them. However it is not as safe as it might sound, flowers can hide predators, especially the camouflaged crab spider which match their colour to the flowers they sit on.

crab spider with hoverfly

crab spider with hoverfly prey

The crab spider here matched the hawthorn flowers so well that I missed it and initially set up to take a picture of the hoverfly, only then did I see the spider!

It has not been a good year for ground-nesting birds so far this spring, with most lapwing and little ringed plover losing their eggs to predators. I suspect mammals at night as the ones nesting on the islands are doing much better. Or at least they were, on Thursday might all the black-headed gull on Long Spit abandoned their nests. Although I don’t know for sure I suspect that something swam out there and ate their eggs, probably a fox or a badger. These mammals are usually not that keen on swimming, but if they are hungry they will go to great lengths to get the food they want, I think small mammals, which are their preferred prey, are in short supply this year, which might be why they are seeking birds eggs more actively.

Despite a bad time for some ground-nesters the pair of oystercatcher are still doing well, with their two chicks growing well. They hatched on Long Spit, moved off to the shore near Tern hide and have now returned to Long Spit, this meant they were not out there on the night of the predator raid. So far the main gull colony on Gull Island shows no sign of being attacked and neither do the tern rafts on Ivy Lake.

 

Life Be(e) Hard

A bee’s life is not just busy, worse still all that hard work can turn out to be in vain, as I saw today, there is always someone out for a free ride.

As it was warm and sunny today I decided to check out a sand face that had lots of nesting solitary bees and try out the new “Field Guide to the Bees”, published last autumn. It was easy to see there were lots of bees and several species. The most frequent were the yellow-legged mining bee Adrena flavipes (or at least that is the conclusion I came to).

Adrena flavipes

Yellow-legged Mining Bee (Adrena flavipes)

These bees nest alone, in that each female has her own nest in which she makes cells, into which she lays an egg and provides a store of pollen for the grub. Bees that live like this are known as “Solitary bees”. These nests are often close together though so you get lots of solitary bees in one place. They collect the pollen using the long yellow hairs on their legs that give them their English name.

Adrena flavipes 2

Yellow-legged Mining Bee (Adrena flavipes) showing yellow legs.

Not all bees are so busy though, some hitch a ride by parasitizing the nests of others. These parasites mostly look like wasps, often being yellow and black. One such lays its eggs in the nests of the yellow-legged mining bee. They fly up and down the sand face looking for nests that are unattended. In this case the parasite was a species called the painted nomad bee Nomada fucata (again if I have identified it correctly).

Nomada fucata in flight

Painted Nomad Bee (Nomada fucata) looking for Yellow-legged Mining Bee nests.

From time to time they will alight and go down a hole to check it out. Sometimes though, they could see that a nest was occupied then the tactic seemed to be to settle beside it and wait.

Nomada fucata waiting 3

Painted Nomad Bee (Nomada fucata) waiting beside an occupied Yellow-legged Mining bee nest.

Once the rightful occupant leaves, the parasite ducks in to lay an egg in an open cell. When it hatches the nomad bee’s grub uses its large jaws to kill the mining bee’s larva and then it grows by eating the pollen store provided by the female mining bee. Her business done she emerges to find another unoccupied nest with cells at just the right stage.

Nomada fucata emerging

Painted Nomad Bee (Nomada fucata) leaving a Yellow-legged Mining Bee nest.

In fact things are even worse for the mining bees as they are also parasitized by bee-flies, which were also present in numbers scattering their eggs outside the bee’s nests.

Elsewhere on the reserve things were fairly quite, but over Ibsley Water the number of common tern had grown to at least 10. They seem to be feeding on emerging insects, picking them off the surface just like the first summer little gull, which was still present. I mentioned to someone that things were ideal for black tern, which mainly feed on insects over water and as I locked up there was one looking very splendid in full breeding plumage, always a treat to see.

At the Woodland hide I saw only one brambling today, a very smart male, I cannot think he will be with us for much longer.