Ringing at Nanjizal - 15/10/15

On Thursday, I joined Ellie and Will to head down to Nanjizal valley (near Land's End) for a morning's ringing at Kester Wilson's fantastic site. We set off just after 6am, arriving for the first net round a little after 7am. It was a perfect morning for ringing, with not a breath of wind, some gloomy cloud cover overhead, and a fair passage of migrants underway.

It was a great morning's ringing at Nanjizal, with a steady stream of birds finding their way into the mist nets between 0700 and 0900, before a much slower pace resumed thereafter. It was great to have flocks of thrushes dropping in and moving west overhead, some of which made their way into the nets. Blackcaps, Chiffchaffs, Goldcrests, Firecrests and the odd Yellow-browed Warbler were present amongst the scattering of willows, bramble scrub and taller conifers, and we ended up catching a good number of the former three species. Aside the birds we did catch, there was a lot more flying overhead in the form of visible migration, the highlights including: 42 Skylarks, 200 Jackdaws, 87 Redwings, a Lesser Redpoll, a Green Sandpiper, 37 Meadow Pipits, a Stock Dove, three Siskins and a Reed Bunting.

In terms of ringing, we managed to do 101 new birds, and processed around 20 retraps. Amongst the most numerous species, namely that of Blackcaps, Chiffchaffs and Chaffinches, were one or two smart birds: five Redwings and two Song Thrushes were great to catch, with one of the latter sporting a very grey rump and upperparts, presumably a continental bird; two re-trap Yellow-browed Warblers were great to see, as were four new Firecrests and a further two re-traps; a new Cetti's Warbler and a retrap Kingfisher added to the colour and variety of the morning's session.

Here are a few images from the morning:

Nanjizal, about nine miles from Land's End

The first Redwings of the autumn have only just appeared in the last week down here in Cornwall, so it was great to ring a few during the morning

It has been an amazing year for Yellow-browed Warblers throughout the UK this autumn, and they have been a regular occurrence in the nets down in Nanjizal over the last week, with seven trapped a few days ago

One of my favourite birds to catch- the cute Goldcrest, this one a male (sporting the bright red crown feathers)

 ...and its scarcer cousin: the Firecrest. We caught six birds during the morning, most of which were new birds

 Cetti's Warbler

 The grey wash to the rump and upperparts of this Song Thrush identifies it as being of the continental race/origin

 The dazzling wing of a Blue Tit- this one, however, is a juvenile born this year. Adults have even more blue on the wing, edging the primary coverts 

Lon-tailed Tit. They are always a delight to catch!

Falmouth Birding update - autumn migration well underway

It has been a while since I had an avian-based update on my blog, so I thought it was about time to catch up with some of the sightings I have had around the area...
It has been great to start seeing some classic winter species arriving, hinting that autumn is approaching its mid-stages of migration: it was great to hear the first 'seep'-calls of Redwings yesterday morning, as the clear night gave way to a stunning morning. These were followed by a fantastic passage of Redwings over campus between 0800 and 0930 today, where flocks of up to 50 passed south-west, comprising over 160 during this time period! Accompanying them were a couple of Mistle Thrushes, Song Thrushes, 30+ Meadow Pipits, 4 Siskins, 4 Chaffinches and a Cormorant (!).

Visible migration, or 'vis mig' as it is alternatively termed, has been great over the caravan over the weekend too: I noted over 100 Meadow Pipits, 50+ Linnets, Siskin, five Skylarks, a Sparrowhawk, two Snipe, two 'alba' Wagtails and five Chaffinches on Sunday, with similar number present the previous day. I am hoping that this trend will continue over the next few days of clear skies and low winds, with a slightly scarcer stray perhaps finding its way into the mix...

In other news, the ridiculous Yellow-browed Warbler influx which is currently underway int he UK has certainly reached firmly down into the south west: I now have this stunning sibe wanderer on my home 'patch' list, when a bird turned up in the Sycamores about our caravan a few days ago! Prioir to this, another bird was heard on campus a day or two earlier. Aside these smart phylloscs, Firecrest numbers have been excellent: I have noted birds either on the coast or on campus every day for the last week, with the as many as five on any one day. I had a great encounter with a pair on the 7th, which are pictured below.

Other sightings of note: Greenshanks, Common Sandpipers, Curlews and Little Egrets on the flats in Penrhyn harbour; Green Woodpeckers on campus most days, with good numbers of Coal and Long-tailed Tits; a significant increase in wildfowl numbers of College Lake, with 17 Wigeons and 26 Teals present on the 10th, hinting towards the arrivals that are hopefully due to continue in the coming weeks.

Here is a more bird-centred mish-mash of images from the last week...

Coot! Great to see these charactful birds, especially coming from an island where one turning up on a small pond was the first in 15 years! Getting up close has been great for photography 

 The autumn colours are really starting to come through now...a Great Tit hiding amongst a tangle of branches

 One of the many Firecrests that have appeared over the last week; there has been a singing male daily on campus for a number of days now

female Stonechat

 It was nice to connect with a handful of smart Wheatears last week at Godrevy, where some Skylarks also pitched down amongst the 170+ Meadow Pipits...

 Skylarks- one of the quintessential elements of autumn passage, with their musical calls overhead a sure sign of good 'vis mig'

 Cormorant on a misty morning at Nanjizal

 It has been good fun to photograph a number of wildfowl species which I have never really spent time observing before now, due to their infrequent regularity on Bardsey. Little Grebes have been a pleasure to watch and photograph, as have the tame Tufted Ducks on Swanpool...

 male Tufted Ducks

Jays have been busy all over the area collecting their winter stash of Acorns. 

Orb-weaving Spiders: nature's great architects

In this blog post I shall be focusing solely on the beautiful and fascinating Garden Spider (Araneus diadematus). This species is a member of the typical orb-weaving spiders (family Araneidae), and is one of the the most noticeable arachnid species encountered from July through to November, occurring across the UK in gardens, hedges, parks and scrub.

Anyone rising early in the last few weeks on a calm, crisp autumnal morning may have been treated to the stunning display of orb-webs that cling delicately to areas of scrub, hedgerows and other favourable hunting grounds. If you are really lucky, then a heavy dew may have descended overnight and vividly highlighted the individual strands of the webs with small water droplets, turning the webs into a beautiful piece of art. This has certainly been a common, and very welcome, sight for me in the last few weeks, and has lead me to try writing a short piece about these superb creatures...

Garden Spiders and their beautiful webs in the early morning light, taken at a nearby nature reserve called the Bissoe Valley

So, who do we have to thank for adding these ethereal scenes to our early mornings? The culprit is the humble Garden Spider, Araneus diadematus. This species, like many others in the Araneidae family, spin large orb webs to snare unwary prey. Typically about 13mm in length in females, and up to 8mm for males, they can grow to a chunky size- the former in particular can spin sizeable webs capable of catching a diverse range of prey items, from butterflies and grasshoppers through to midges, shieldbugs and species of bees and flies.

Female Garden Spider lying low after a bought of heavy rain overnight. I wonder what effect dew and water droplets have on the catch of Orb-weaving Spiders?

The pregnant females are particularly bulging in appearance, due in no small part to the swelling of eggs. These will be packaged into a silk egg sac, which is laid onto branches, in sheds, or in other such sturdy places. The small eggs will hatch out in the spring, into a burst of tens of small yellow Spiderlings. These will then disperse, grow, and eventually set about building their own delicate masterpieces- with no tuition or input from the now-deceased mum.

Another female Araneus diadematus, clinging onto to its central cluster of threads. This web has had a productive day's catch, as can be told by the 'by-catch' items that have just been left. My friend and excellent photographer Will Hawkes is undertaking an interesting study into the relationship between size of spider and number of prey items left over (i.e. not consumed)

So how do they actually construct these architectural masterpieces? It is amazing to think that these spiders are able to spin webs across gaps which they can't actually physically cross, and which can be over 50 times the length of the spider! As a side note before I attempt to summarise the process, it really is worth watching this super cool time-lapse of a Garden Spider creating its web.
To begin the process (which the Orb-weavers typically carry out at night, before the main 'hunting' period during daylight hours), the spider spins a very fine thread of silk, which it allows to drift from one side of a gap to the other. Once this thread has made contact with the far side, it adheres and allows the the spider to pull it tight and strengthen it numerous times with additional threads. Once the main thread is strong enough to support the rest of the web, two additional threads will gradually be added to form a Y-shaped 'web'. This Y will be the primary foundation for the rest of the web...at this point the spider will now go about adding a number of radials to the web, which sets the base ready for the sticky circular threads. An amazing feature of this stage is that the spider will construct a non-sticky spiral of thread from the centre to the periphery, which allows it to move around during construction without getting stuck!

After strengthening the central 'perch' with about five circular strands, the spider now makes the fundamental circles of sticky threads that perform the crucial role of ensnaring victims. The spider will start from the outside moving to the centre, and will use the non-sticky spiral to move between the layers; as it makes these closely-spaced circular threads, it will remove the non-sticky spiral. The reason that the circular sections of the web are so exact in distance between each other is simply because of the way they are made: the spider picks the thread from its spinner with its hind leg, and fastens it onto one of the radials- it then repeats this as it continues round, securing the circular strands to a radial line each time one is encountered. Eventually, the web is finished, and the creator can now sit happily in the centre, and await its prey.

A web in construction, with the spider in the process of spinning the sticky circular sections as it works from the outside to the centre

Perfection: a near flawless masterpiece awaiting a productive day's hunting

The spiders use a variety of mechanisms to prevent themselves from falling victim to their own success...besides the spinning of non-stick threads in the course of construction and operation of the web, the spider also has very fine hairs and a non-stick surface on the tips of its legs which make sticking less likely. Most of the species in the family Araneidae have three tarsal claws, and the third of these is thought to have a particularly non-sticky function, thus forcing the spider to walk solely on these in some circumstances.

The Garden Spider may rebuild these webs every day, as anyone who continually walks through awkwardly-placed webs may testify. The spider will often consume what is left of the old web so that the proteins used to make the web can be recycled and re-used in the next one.  

 Another chunky female Garden Spider

Garden Spiders spinning up an unfortunate Common Green Grasshopper

When prey items become tangled in the sticky threads, the Garden Spider will quickly pick its way over to the victim, and promptly wrap it up in a layer of silk. It will then devour the victim straight away or return sometime later.

 It is great to see the sticky-ness of certain strands at work in all of the dew-covered webs above: can you see that most of the droplets are only sticking to the circular sections of the web? Most of the radial sections and the spider's central perch (non-sticky) are devoid of droplets. 

So there we are...a bit of a focus on the species responsible for the amazing webs which hang unassumingly in parks and scrubland areas all across the UK. Will you look at one of these superb arachnids in a different stead next time you see one?

References:

- Encyclopedia of Life - Garden Spider

- 'Nick's Spiders' 

- Buglife factsheet

- The RSPB - Garden Spider

- British Arachnological Society

- Wikipedia on Araneus diadematus 

The Ivy Mining Bee (Colletes hederae)

Last week I visited a stunning local reserve with fellow young photographer Max Thompson. The area we visited was called the Bissoe Valley- an old mining site where a restoration programme set up in 1986 has now transformed the old an polluted works into a flourishing nature reserve. The habitats present range from deciduous woodland, regenerating heathland, small ponds and a freshwater river. This great mix of habitats makes it a great place for wildlife, and the focus of our particular visit was on a particular invertebrate...a small striped bee

The Ivy Mining Bee (appropriate considering the past of the reserve) is a scarce species in the UK, being restricted to the south-west. This is partly because it was first recorded just fifteen years ago, in 2001. The species flies from September to mid-November inclusive, as it depends upon the flowering of Ivy as its main food and pollen source. This species gets the other third of its name from the colonial habits of tunnelling- the nests are situated in excavated burrows as deep as 30cm in soft soil. The number of these nests can increase into the tens of thousands! 

At the particular site in Bissoe, a small clearing in the scrub habitat saw a sandy area of bare ground possessing hundreds of these nests- amounting to over 1500 individual bees at least! As the day warmed up from the crisp start, it was great to gradually see individuals popping out of the burrows, perhaps taking a little time to warm up outside the entrance, before flying a short distance and alighting on a nearby oak- now in full sunshine. More and more bees emerged from the maze of tunnels s the morning warmed up, until the area was quite literally a 'hive' of activity, with hundreds of bees darting this way and that.

An Ivy Mining Bee emerging from its tunnel

It was great to see some really interesting behavioural features, which max had previously seen and told me about. One such event was that of the mating. This process would begin when a queen- a much brighter orange bee perhaps twice the size of the males- would emerge from one of the holes, and proceed to be inundated with as many as ten different males. These would combine to form a sort of mating 'ball', full of enthusiastic males trying to perhaps get the best position on the poor queen. Eventually - for whatever reason - many of the males would disperse, and leave just one or two left with the queen. Then a little later, we saw the queen fly off with the successful male, and the two chose a spot on an oak a little way away to conclude the process. 

A mating 'ball' ( in the bee world, there are roughly seven males to a female)

Some more images of this smart species:

A focus on the smaller side...

Over the last few weeks, it has been great to wander around the various wildlife-rich areas around Falmouth and spend a while looking at the smaller elements of nature...

Even when it is windy and dull, there is always something to look at, whether it be a bulky House Spider sheltering in a away in a hidden crevice, or perhaps a small Rove Beetle that scurries across the ground in front of you. Will Hawkes and I have had particular fun in finding a plethora of different Hoverfly and Shieldbug species lurking around the rich hedgerows and rank grassland patches nearby. We have almost encountered 10 species of the latter, whilst identifying the former is proving a little more tricky in some instances. It is great to find and observe the various forms of arthropods whilst the weather holds up and many are still actually around (not looking forward to the depths of winter!).

The spiders have been particularly entertaining, demonstrating a surprising diversity of prey items wrapped in neat packages within the webs of the Orb-weaving Spiders (Araneus diadematus). Anything from miniature midges to shieldbugs, grasshoppers, moths and even butterflies have been unfortunate enough to meet their end in these delicate structures- a few morning ago I had a great time photographing the stunning webs down at the Bissoe Valley with fellow photographer Max Thompson (see below).

Without waffling on too much, you can check out a bit of the invert diversity that we have encountered over the last week or two, and I shall try and give a bit of a caption for each :)

A couple of shots of the amazing webs of the Orb-weaving Spiders (mostly Araneus diadematus). A few mornings ago, I was at a nearby site in the Bissoe Valley and had the pleasure of photographing these stunning webs as the rising sun gave a delicate back-lighting and the light dew highlighted the strands

This little arachnid is a Zebra Jumping Spider (Salticus scenicus), a member of the Salticidae family. These species have incredibly adept eyesight, hunting primarily with the use of this sense. They move with a jerky motion over surfaces, 'hopping' or jumping using their hydraulically-powered legs

One of the many hoverfly species encountered recently- what appears to be Sericomyia silentis

A Knot-Grass Caterpillar, found in the garden on campus

Another caterpillar, this time a massive species that somehow turned up in a mist net at Nanjizal! An Eyed Hawkmoth

Some moth stuff...

I have been running my small heath trap fairly consistently outside the caravans for the last few weeks, but the catches have largely been quite low in both diversity and number. I think this is primarily due to the large moon, as last night saw over 20 moths in the trap, including some smart species like Beaded Chestnut, Autumnal Rustic, Feathered Ranunculus and Pink-barred Sallow. I am looking forward to a few more autumn moths in the coming week, especially with the use of a couple of moth traps on Uni campus grounds...

Green Carpets have been quite regular in the trap, and very welcome too!

A Copper Underwing of either of the two species- it looks to be Copper Underwing after examination of labial palps, underwings and forewing pattern, but I remain unconvinced that the two species (Svensson's Copper U vs. Copper U) can be identified on external features alone

Pink-barred Sallow- a classic autumnal moth

It has been great to see the odd Hummingbird Hawkmoth dotted around, especially this individual on campus a few days ago

Gorse Shieldbug (Piezodorus lituratus)

And now for a few 'macro'-centred images that I have taken over the last week or two (some are intentionally abstract...)

Oxeye Daisy at sunrise

Orb-weaving Spider's web 

A backlit Moss shot: Mnium hornum

Fungi of some sort- ink-caps?

Sycamore 'keys'

Fern reflections

Backlit ferns in the early morning light