Friday, 18 January 2019

Rossie School Bird Ringing 2019: Session 3

It was a bright, frosty morning and the wind remained mercifully light. This third morning session of the 2019 was again centred around the Old Football Field with 2 mist-nets in use. An Mp3 player with speaker was deployed playing redpoll song in an attempt to lure any passing birds down to the net. Alas, it transpired the usual flock of 30+ redpoll were not in the area but there were siskin and goldfinch instead. The second net was deployed next to a hanging bird feeder filled with nipped sunflower seed. Before packing up a midday 24 birds of 8 species had been caught; all bar two coming from the net with the hanging feeder. 



Six siskin was the highest number caught at this site in a single session. Indeed, this morning was slow to get going and suddenly at 11:30 I had a net full of birds: 13 of 7 species! A coal tit caught for the fourth time during this session is the most 'trap happy' individual so far. 



Adult male goldfinch

1st winter male siskin




Footnote

These activities were carried out under a permit issued by the British Trust for Ornithology on behalf of Scottish Natural Heritage that allows the catching of birds for ringing purposes in compliance with the Wildlife and Countryside Act 1981 (as amended). Further information on the UK Bird Ringing Scheme can be found here.

Monday, 14 January 2019

Rossie School Bird Ringing 2019: Session 1 & 2

The first two ringing sessions of 2019 were centred around the Old Football Field with 2 to 3 mist-nets in use. Mp3 players were deployed with redpoll and siskin song in an attempt to lure them down to the nets from the tops of the nearby alders. Both sessions caught a combined total of 12 birds of 7 species and included 6 previously ringed birds. 


Summary of birds caught at Rossie School for 2019
Only 3 lesser redpoll and 1 siskin were caught over two sessions with numbers of roving birds declining over this period. So far this 45 lesser redpoll have been caught at the Old Football Field or in the nearby stands of regenerating birches. There has not been a sighting of mealy redpoll since before Christmas and it is likely they have left the site. 


An adult male Lesser Redpoll with rosy flush to its throat and breast


Tail feathers of the above Lesser Redpoll showing broad, rounded tips indicative of adult feathers
Footnote

These activities were carried out under a permit issued by the British Trust for Ornithology on behalf of Scottish Natural Heritage that allows the catching of birds for ringing purposes in compliance with the Wildlife and Countryside Act 1981 (as amended). Further information on the UK Bird Ringing Scheme can be found here.

Saturday, 12 January 2019

Hoverflies Overwintering in Leaf Litter 2019 #4

12/01/2019 Mains of Usan, Montrose , Angus NO722554 - sycamore with dash of elder, hazel, beech and ash under broadleaves and scots pine - 1 Tesco's Bag for Life.

Hoverflies
Syrphus sp. - 2
Parasyrphus sp. - 1
Epistrophe grossulariae - 1
Melanostoma sp. - 1 (still active)

With exception to E. grossulariae, the remaining larvae will need to be reared to enable identification to species. 

From left to right: Syrphus sp., Parasyrphus sp. & Epistrophe grossulariae

Melanostoma sp. with a Lauxaniid powering away

Other Diptera
Lauxaniidae - 36
Lonchopteridae - 10
Limoniidae - 4
Fanniidae - 2

Friday, 11 January 2019

Overwintering Hoverfly Larvae in Leaf Litter

Quite a few of us at the UK Hoverflies Larval Group are hand-sorting bags of leaf litter at the moment in search of larvae. Others, I hope, might be thinking about joining us. The majority of encountered hoverfly larvae will be those that predominately feed on aphids such as Syrphus, Epistrophe, Dasysyrphus and Parasyrphus. During the summer these larvae would have gorged themselves on aphids and when sated entered a torpid state to see out the winter. Either they made their own way into the leaf litter or dropped with the leaves in the autumn. Once there they remain at rest conserving their energy until spring when puparation occurs and if all goes well an adult emerges.

Syrphus sp. in diapause overwintering in leaf litter

Epistrophe grossulariae (centre) in diapause overwintering in leaf litter

Dasysyrphus albostriatus in diapause overwintering in leaf litter

Parasyrphus sp. in diapause overwintering in leaf litter

Overwintering larvae can be found hiding in the folds of dried and crinkly leaves at the surface but some will be among the moist, compacted leaves beneath, and it pays to take a sample of both. Most can be identified to genus but getting to species usually requires rearing the larva to adulthood. One advantage of collecting wintering larvae to rear in captivity is that they will not need so much care: they have finished feeding and only require a cool, dark place that is neither too dry nor too wet to get through to the spring. A simple rearing method is to place a larva on a moistened scrap of kitchen towel and place inside a yogurt pot (or similar container) capped with a taut piece of kitchen towel/mesh netting held in place with an elastic band. More details on this method can be found here

Yogurt pot with larva inside capped with kitchen roll held taut by elastic band

However, the bright green Melanostoma larva is the exception. They remain active throughout the winter feeding on other fly larvae such as Lauxaniids and Lonchopterids that also live in leaf litter, particularly in the moist layers where glean micro-organisms that form on leaves. At this stage of winter some of the Melanostoma will have finished feeding and entered a torpid state until spring whilst others will continue to feed. This means that any larvae brought into captivity for rearing should be offered a couple of prey items just in case they are still hungry. More information on Melanostoma occurring in winter leaf litter can be found here.

Melanostoma sp. feeding on a lauxaniid larva (Diptera)


Monday, 7 January 2019

Hoverflies Overwintering in Leaf Litter 2019 #3

07/01/2019 Rossie Spit, Montrose, Angus NO705565 Leaf litter sycamore with dash of elm, beech, oak and ash - 1 Tesco Bag for Life
Hoverflies
Syrphus sp. 3
Melanostoma sp. 1 - small 3rd instar
All larvae will need rearing to adulthood to enable species identification. 

Melanostoma sp. a rather paler individual than normal

Syrphus sp.


Other Diptera
Lauxaniidae 35
Lonchoptera sp. 3

Other insects included a very vividly coloured Hawthorn Shieldbug Acanthosoma haemorrhoidale that rocked an admirable pair of 1980s shoulder pads. A wonderful splash of green colour set amid the decaying brown leaves. 

Hawthorn Shieldbug Acanthosoma haemorrhoidale

Hawthorn Shieldbug Acanthosoma haemorrhoidale

Wednesday, 2 January 2019

Hoverflies Overwintering in Leaf Litter 2019 #2

02/01/2019 Dun House, Montrose, Angus NO668598 Leaf litter sycamore with dash of beech, birch and yew from wooded glen - 1 Tesco 'Bag for Life'

Hoverflies
Syrphus sp. 19
Parasyrphus sp. 3
Melanostoma sp. 2

All larvae will need to be reared to adulthood to confirm species.

Syrphus sp.

Parasyrphus sp.

Melanostoma sp.

Other Diptera
Lonchoptera sp. 6
Fannia sp. 4
Lauxaniidae 2
Tipulidae 1
Limoniidae 1
Phaonia sp (Muscidae) 1

I managed to capture an 'action shot' of a Phaonia larva devouring an unlucky lauxaniid. They are highly efficient predators and spend the winter hunting anything their mouthparts are capable of piercing. Several years ago I co-authored a paper on the feeding mechanics of Phaonia subventa that I had found, observed and reared from leaf litter. I've yet to rear any other species of Phanoia from Scottish winter leaf litter. 

Phaonia sp. devouring a lauxaniid

There were some other cool insects taking refuge in the leaf litter including this delightful Parent Bug Elasmucha grisea. Apparently, both sexes overwinter and then mate in the spring; the male soon dies leaving the female to brood the young alone. The individual I found today was in my opinion incredibly photogenic. In another life I could easily delve deeper into the Hempitera. 
Parent Bug Elasmucha grisea

Parent Bug Elasmucha grisea



Tuesday, 1 January 2019

Hoverflies Overwintering in Leaf Litter 2019 #1

01/01/2019 Dunninald Castle, Montrose, Angus NO705540 Leaf litter sycamore with some beech (Tesco Bag for Life) from roadside verge
Hoverflies
Syrphus sp. 4
Melanostoma sp. 2
All larvae will need to be reared to adulthood for species identification. 

Syrphus sp.

Melanostoma sp. a lovely bright green individual


Other Diptera
Lauxaniidae 16
Lonchoptera sp. 3
Fannia sp. 1

Lauxaniidae (Diptera) larva

Lonchoptera sp. - 3 mm of armour plating


Lonchoptera sp.