Showing posts with label Climate Change. Show all posts
Showing posts with label Climate Change. Show all posts

Sunday, 2 July 2023

Puffins- the spell of the Northern Monks.

The little tourist boat out of Ulver Ferry on the Isle of Mull drew towards the towering cliffs of Lunga, largest and northernmost of the Trennish Isles, the chain of rocky little basalt islands in the Inner Hebrides, north of the famous Fingal’s Cave on the isle of Staffa, that great monument to undersea volcanism and geological forces. The water we crossed was crystal clear, and rich in life, fish weaving between fronds of waving kelp beneath the surface, moon jellies, and occasionally more unusual cnidaria, drifting everywhere. At one point even Common Dolphins were leaping beside us.  We docked at a rocky promontory on the island and made our way ashore on the columnar basalt, climbing a short cliff path. The skipper had warned us the birds would hypnotise us, that we’d risk falling into a trance on the cliff path, and would have to come back to the boat without seeing the spectacular heart of the seabird city which lines the steepest cliffs. His warning was spot on, but not heeded.




We sat up on the cliff top, among the wild flowers, the Bird’s foot trefoil and Burnett moths, on the rabbit-grazed, short grass, and watched the comings and goings of the Atlantic Puffins (Fratercula arctica) for hours. Birds flew in off the clear blue water, on wings beating rapidly, with thick, vivid coloured beaks full of silver sandeels.  Adults with food swiftly disappeared into their burrows, even Puffins are not averse to nicking their neighbours’ food, and to the gulls and skuas a Puffin with food on land is an obvious target.  So, they take their food underground hurridly, and unload it for the subterranean Puffling, the single, fluffy youngster waiting in the burrow.  Puffins without bills full of food seemed to enjoy a more leisurely lifestyle, taking some time to enjoy the sun and each other, pairs bill-rubbing and calling to each other, enjoying the bonds which hold them together, companionable, almost romantic. We were, naturally, enchanted by these entertaining little seabirds, and never made the journey across the little island to the spectacular Guillemots and Kittiwakes up on the towering sea stacks.




My paternal Grandma loved Puffins, and as such I must have drawn and painted hundreds of pictures of them, and bought puffin calendars and birthday cards for her every year. Images of them adorned her home.  They were here favourite bird, and as such have always held a special place in my heart. However I was in my mid-twenties by the time I saw one, on another chain of islands on the West coast, right down in the Scillies.  Puffins tend to live far from us, on rocky offshore islands, like the Scillies or the Trennish, or famously on Lundy, where the Bristol Channel meets the Atlantic.  They visit the coastline only briefly, setting up in April, and gone by the end of July. Their vanishing act is thorough and though wintering puffins were encountered at sea from time to time, it wasn’t fully understood until the advent of geotagging.  Once their Puffling has come waddling out under the sky for the first time, and taken to the sea, the parents remaining tie to land is severed. They shed the bright, temporary sheath which has grown around their bill, and darker feathers grow around the eye, masking the big, white face patches.  They loose the ability to fly during the Autumn moult, and spend the winter upon the ocean waves, living like the penguins of the Southern hemisphere, undertaking deep dives, wings adapted for ‘flying’ underwater. The black and white countershading Puffins, plus several related Auks share with Penguins are an example of convergent evolution, where similar evolutionary pressures lead to similar adaptations.  They retain the ability to fly only because of the need to avoid land predators, and only in the breeding season, to reach their cliff-top nesting sites, and they are at their most graceful underwater.  Then, come March or April, they return to their home island, and reunite with their lifelong partner, smartly attired once again. Some compare Puffins to clowns, given their colourful features and ‘eye makeup,’ and their scientific name compares them to monks, Fratercula arctica means ‘little Brother of the North.’ The name Puffin once applied to any burrow-nesting sea bird, hence the confusing scientific name of the Manx Shearwater, Puffinus puffinus.




Puffins are members of the Auk family, Alcidae, and are related to the Guillemot and Razorbill, as well as the extinct Great Auk. The family resemblance is apparent.  Unlike their relatives, puffins nest not on precarious ledges on the cliffs, but in burrows at the cliff-tops, usually taking advantage of those abandoned by rabbits, though they are capable of digging their own, and often do, take note of the sharp grey claws on their feet next time you are close to one.  A single egg is laid underground, in a chamber carved out for the purpose. The chick remains underground in relative safety, out of the reach of Herring Gulls and Raptors which occasionally prey on Guillemot and Razorbill chicks. Puffins also differ from their relatives in their winter habits. Razorbills and Guillemots can often be seen in winter, forming big rafts just offshore from their breeding colonies, remaining visible to birders onshore all year round, but Puffins are always absent from these agglomerations, preferring to spend the winter in the vast, open Atlantic, the Bay of Biscay and the North Sea, rich fishing grounds to which they have been tracked by modern telemetry techniques.




Puffins have a number of predators, with Gulls and Arctic Skuas all too keen to steal their hard won catch of Sandeels, which the young Puffling relies on almost exclusively, and Great Skuas, Great Black Back Gulls and birds of prey such as Peregrines, will occasionally prey on the adult Puffins. They are even, in some parts of their range, still hunted by man, though not in Britain.  Climate Change, and the loss of Sandeels as a result, and as a result of overfishing remain the biggest threats they face. They are confined to relatively few colonies around the North Atlantic, largely on islands off North America and North-Western Europe, and this reliance on a small number of sites led to the Atlantic Puffin’s listing as Vulnerable by the IUCN, and they are Red-Listed as Birds of Conservation Concern.




Yet at some of their colonies they are thriving, and one of those seems to be that of the Isle of Lunga. Rich, clear Atlantic seas offer them the food they need, and they are bothered little by the tourists who continue to visit their island breeding sites in considerable numbers. They are confiding and allow close approach, and photography. A few nest still at Bempton Cliffs in Yorkshire, alongside the Gannets and the occasional visiting Albatross, and though closed this year given the unfortunate impact of the ongoing HPAI epidemic, the Farne Islands still host a healthy population of these charming, entertaining little sea birds. Go and see them.





 

Wednesday, 4 January 2023

High Fashion and Green Metal in an Essex Summer: The Lestidae Damselflies

 As it is (ed: Not long past) Christmas, and I have already written of a decidedly Christmassy species, I thought, in the dark of St Stephen’s Night, to revisit the insects with which I spent a privileged summer, through the coastal marshes of Essex. The Lestidae damselflies, or Emerald Damselflies, come in a range of shades from key lime pie green, to metallic fir tree tinsel green, some bearing a dusty blue pruinescence. They are desperately fashionable too, subject of many treatises, management plans and UK Wildlife Podcasts, in part because of their undoubted beauty, more subtle than that of the splendid Calopteryx spp - perhaps more of them later- and less easily spotted than the big Aeshnids I wrote about before. Essex is their spiritual home- and arguably one of the epicentres of their remarkable colonisation of these islands. All four breeding species are found in the county, and I had the privilege of meeting them all over the summer of 2022.


Scarce Emerald Damselfly nomming a Blue Tailed Damselfly (Ishnura elegans)



Willow Emerald Damselfy, RSPB Bowers' Marsh, Essex. 

My first encounter with these splendid creatures was a couple of years ago at RSPB Rainham Marshes, where I met a gorgeous, deep bronze green insect hanging serenely on some wetland tree that may or may not have been the one from which it took its common name. This slim and delicate creature was a Willow Emerald (Chalcolestes viridis) a stunning creature which immediately caught my eye, especially as it was October, when all but the hardiest Common Darters and Migrant Hawkers had reached the end of their season. The Willow Emerald is unique among British odonata as it does not lay its eggs in water, but instead, in neat incisions made in woody vegetation overhanging water with a modified ovipositor. I have witnessed them laying eggs like this while still in tandem, the male gripping the female with his anal claspers, protecting, or jealously guarding her. From these eggs the tiny prolarvae emerge in spring, and drop into the water below to continue their life cycle, much more typically. Any which fail to find water do not make it, but conversely, being to an extent free of the need for water during late summer oviposition offers an advantage in a drying climate.  This species was first recorded breeding in the UK in something like 2009, in Suffolk. On a September walk by the Thames at Tilbury in 2022, with my good friend Chris, we found hundreds of these beautiful, bronze green insects, hanging out on Brambles tens of metres from fresh water. It is a species which has undergone a meteoric rise. Look for an all-green Damselfly, sometimes shimmering bronze in the sunshine as the light catches its iridescence, with clear wings (mind those flashy Calopteryx!) white pterostigmas (the dots in the ‘outboard’ corners of the wings), hanging out on marginal woody vegetation near still or slow-moving water.

Willow Emerald, Tilbury, September 2022


A few years later, while walking among the ditches at an EWT nature reserve way off the beaten track yet not too far from Basildon. Hanging on a branch, apparently relatively freshly emerged, was a beautiful male Scarce Emerald (Lestes dryas). Contrary to its English name, this species seemed very numerous on the sites where it lived. A hulking brute of a damselfly, size being a key if not universally reliable way of separating it from the smaller Emerald Damselfly (Lestes sponsa), and another species identified as having a distinct upward population trend, it likes Sea Clubrush choked ditches, sometimes to the consternation of site managers irked by its insistence on enjoying exactly the habitats wading birds do not, and often co-occurs on the coastal grazing marshes also favoured by Small-Red Eyed Damselflies and Ruddy Darter Damselflies. Like all Odonata it is an active predator, adult and nymph, largely taking small flies,  but not averse to dining on its distant relatives. At RSPB Old Hall, what I initially took to be a mating pair of Blue-Tailed Damselflies, turned out on closer inspection to be a Scarce Emerald feasting on the corpse of a Blue-Tailed Damselfly. In addition to an impressive display of predation, though I had no way of telling whether the Emerald had caught its prey on the wing or simply made a fortuitously (for the Emerald) timed landing, it represented a good chance to compare the blue bits of the two species. The steel blue pruinescence, a dusting of scales which fades with age, contrasted strongly with the almost luminescent looking blue tail-light of the commoner species.  Scan through the big crowds of Blue Tailed Damselflies for this big beast, and use your close-focus bins or a good photo to identify it by the pruinescence covering the whole of the first two segments of the abdomen, and the big, bent-paddle claspers at the back end to separate from male Lestes sponsa. A slightly different pattern of green and pale cream on the thorax separates the females of these species.  Look for them in June and July, I saw few of them after the big heatwave of 2022, for reasons unknown, perhaps it baked off the adults or desiccated any late developing nymphs.


Scarce Emerald (female) Essex 2022


Scarce Emerald (Male) Essex 2022

Historically, the commonest of the Lestidae in the British Isles, and still the one you’re most likely to encounter outside of South Eastern England, is Lestes sponsa, the Emerald Damselfly, you may hear it called the Common Emerald Damselfly.   This species has undergone something of a decline of late, like many of our odonata, as documented in the State of Britain’s Dragonflies report. It is hard to separate from L. dryas, I recommend a good book with the illustrations of Richard Lewington in it and a good pair of low-magnifying small binoculars for close focus, though any particularly small Lestes-with-blue-bits is likely to be one. Sadly I encountered just a few of this species during my summer transects.

Emerald Damselfly, Essex, 2022


The fourth species is the newest, and perhaps the slowest colonising, the beautiful and distinctive looking Southern Emerald Damselfly (Lestes barbarus). This is a gorgeous, key lime pie of an insect, with its dark green metallic upper surfaces contrasting with the pale, green-tinged yellow of its undersides, boasting a unique and instantly recognisable (yes, really) bicolour pterostigma, half milk white, half blackish brown. It has distinct ‘antehumeral stripes,’ look for markings like braces on its thorax. Its stronghold is on Canvey Island, of all places, I am advised a particular ditch is a good place to look, but I found it on the site near Basildon, where it was a new record. More delicate looking than the other three, it was first recorded in Britain in 2002, in Norfolk, and it’s been gradually colonising low-lying Essex since being discovered at Wat Tyler Country Park by Neil Phillips in July 2010, with other early records coming from Gunners Park, Shoeburyness in 2012. It is a more committed climate change rebel, and habitat specialist, than even the Willow Emerald, relying on ditches drying up in late summer for oviposition. I could scarce believe my eyes when I found one near Basildon on an EWT reserve. These species are moving so fast and unpredictably with their quiet invasion that they are one group in which the observations of keen eyed amateur naturalists and local surveyors can make real changes to known distribution maps.

Southern Emerald Damselfly, EWT site, Essex. 



So think of them on these winter days, and dream of them shimmering beneath a warm summer sky. Their season will roll around soon enough. Get yourself a good dragonfly book, a good pair of bins, and, come June, go to your favourite wetlands. You may just find yourself a new favourite insect there.

Southern Emerald Damselfly

*This blog has been edited since posting to correct the timeline of Southern Emerald colonisation and credit the finder.