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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Insects on the Up?

The progress of the season has been rather erratic this year, with spells of very warm or even hot weather interspersed with much colder days. Overall I think that we are still a little behind the average of recent years, but it is a very mixed picture.

Sunday was a fine, warm, sunny day with little wind, ideal for insects and I saw my first beautiful demoiselle, broad-bodied chaser, four-spotted chaser and emperor dragonfly of the year. The four-spotted chaser had emerged from the Centre pond, I think th efirst time I have proved that they have done so there, although I have seen individuals there a number of times. Numbers of large red, common blue, azure and blue-tailed damselfly are also continuing to build.

I am trying to look more closely at the bees on the reserve this year, Blashford has a lot of dry ground with sandy slopes, ideal for solitary bees. In fact “brownfield sites” such as Blashford are particularly good for bees as they often have variations in soil type, slopes and banks ideal for nesting.

Andrena bicolor

Andrena bicolor

Gwynne’s mining bee, Andrena bicolor is one of our commonest spring mining bees and also has a summer brood, it is a close relative of the much rarer grey -backed mining bee, Andrena vaga which was found on the reserve for the first time a couple of weeks ago. The rarer species is still around, but not in the same numbers as a fortnight ago, some of them are getting worn now and so look rather like the much commoner ashy mining bee Andrena cineraria.

ashy mining bee excavating

ashy mining bee Andrena cineraria excavating a nest tunnel.

For several years now there has been increasing evidence of an overall decline in total insect abundance, it is very hard to prove absolutely but accounts of declining moth trap catches and a general scarcity of many insects is attested by many. Older people will remember that when travelling any distance by car in the summer it was necessary to clean many squashed insects off the windscreen. Of course more aerodynamic cars may be a factor too. Whatever the reason it has become much harder to find many insect species in the average summer these days. It was pleasing to see a fair few hoverflies out yesterday including a number of Cheilosia species, a rather difficult genus of mainly black species, the identification of the images below maybe open to revision!

Cheilosia bergenstammi male

Cheilosia bergenstammi (male)

Cheilosia impressa

Cheilosia impressa (female)

Despite the warmer days the nights are still quiet cool and so the moth trap has remained quiet. The pick of the catch was a chocolate-tip moth, it is evidently quiet a good year for therm as this was the third we have caught recently.

chocolate-tip

chocolate-tip

The only grasshoppers and crickets about at present are a few tiny nymphs, but this is the time for finding adult groundhoppers, although the only one I saw was a common groundhopper, but at least it posed for a picture.

common groundhopper

common groundhopper

It would be good to think that we are turning a corner in the insect decline, unfortunately I doubt it, I suspect the wider environment is continuing to become less insect friendly. Although some of this is down to the use of very effective insecticides and industrial mono-culture farming, it is also our overall failure to leave any space for them, even where it would be easy to do so.

Oh, to Bee in England…

As though to emphasise the change in season today was one of those rare days when it was possible to see both brambling and swift at Blashford Lakes an opportunity that lasts for only a few days.  When I started birdwatching in the Midlands our equivalent was seeing fieldfare and swallow in the same place, on the same day. The brambling were at least 2 males at the feeders and the swift at least 14 over Ibsley Water.

Despite the remaining reminders of winter it felt very spring-like, with orange-tip, green-veined and small white, comma, peacock, brimstone, holly blue and several speckled wood butterflies seen, along with the year’s first damselfly, the large red.

After last night’s thunder storm I was not surprised that the moth trap was not over-filled with moths, although the catch did include a lesser swallow prominent, a pale prominent and a scarce prominent, the last a new reserve record, I think.

The warm weather has encouraged a lot of insects out, I saw my first dark bush cricket nymph of the year near the Centre pond. Nearby I also saw my first dotted bee-fly, this species used to be quite scarce but can now be seen widely around the reserve, although it is well outnumbered by the commoner dark-bordered bee-fly.

dark bush cricket nymph

dark bush cricket nymph

The wild daffodil are now well and truly over but the bluebell are just coming out.

bluebell

bluebell

A lot of trees are in flower now or are shortly to be, the large elm on the way to Tern hide is still covered in flower though.

elm flowers

elm flower

Trees are a valuable source of food for a lot of insects and the find of the day was a species that makes good use of tree pollen. I had spotted what I at first thought were some nesting ashy mining bees Andrena cineraria, but they did not look right. That species has a dark band over the thorax and black leg hairs. This one had white hairs on the back legs and no dark thorax band. I took some pictures and it turns out to be grey-backed mining bee Andrena vaga, until very recently a very rare species in the UK which seems to now be colonising new areas.

grey-backed mining bee 2

grey-backed mining bee

They make tunnelled nests in dry soil and provision them with pollen from willows for the larvae.

greybacked mining bee

grey-backed mining bee with a load of pollen

The same area of ground also had several other mining bees, including the perhaps the most frequent early spring species, the yellow-legged mining bee.

yellow-legged mining bee 2

yellow-legged mining bee (female)

 

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.