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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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.