Month: February 2018

If you saw yesterday’s blog post, you will no doubt have some idea what a murmuration is – basically, a flock of European Starlings (Sturnus vulgaris) coalescing into a coherent flock just before they settle down to roost for the night. In case you missed it, here’s the video again:

There are two schools of thought as to why Starlings form these spectacular pre-roost murmurations. The first theory is the “safer together” hypothesis. Get yourself into a big, distracting flock and there’s more chance of confusing a predator, such as a Peregrine and less chance of being eaten before you go to bed. The second hypothesis is the “warmer together” idea wherein more birds roosting together will stay warmer through the night. The murmuration I videoed last night comprised several flocks with an estimated total of about 5000 birds, I reckon.

Anyway, last year there was a paper in Plos One that discussed a citizen science effort to try and find the most likely explanation for Starling murmurations. Anne E. Goodenough, Natasha Little, William S. Carpenter, and Adam G. Hart reported how flock movement and biomechanics have been the focus of research into murmurations, but efforts to find solid evidence of an explanation of this wonderful sight has been limited.

They collected data on size, duration, habitat, temperature and predators from members of the public, citizen scientists, who had observed more than 3000 murmurations. Sightings occurred in 23 countries but most were in the UK across lots of different habitats. Murmurations occurred mostly from October to early February with the average flock containing more than 30000 birds, but one murmuration reported as having 750,000 birds. The murmurations lasted on average just under half an hour, although the longest displays were at beginning and end of the season, which may be down to longer twilight time.

The team reports that birds of prey were sighted at almost one in three murmurations and that the size of the murmuration was bigger if raptors such as Harriers, Peregrines and Sparrowhawk were in the location. If a raptor was in close proximity to the flock, then the flock was more likely to end with all birds going down en masse to their roosting site. Temperature correlated negatively with murmuration duration.

“Our findings suggest that starling murmurations are primarily an anti-predator adaptation rather than being undertaken to attract larger numbers of individuals to increase roost warmth,” the team concludes. Earlier research by a different team had simulated a Starling flock to assess how confusing it might be to a raptor hoping to catch prey on the wing and supports the “safer together” hypothesis too.

This kind of self-organising flocking behaviour is common in shoals of banded killifish, among foraging ants, and in herds of migrating wildebeest, the team adds.

As regular readers will hopefully have realised by now, you don’t need to go too far from home to see astonishing natural wonders. Just a mile or so from our front door here in the Fen Edge north of Cambridge, for instance, I spotted a starling murmuration at dusk. It was happening over the main road out of the village of Rampton and the fields that flank it. So, having seen it in passing, Mrs Sciencebase and I headed there again today to get some video.

The sight and the sound were amazing, thousands of starlings swirling and whirling as they come into roost in the hedgerows just outside the village of Rampton as you head towards Willingham. There was also a Tawny Owl taunting some of the starlings along the hedgerow and a Little Owl calling from the field beyond; although neither of those feature in the video montage, I’m afraid.

In terms of why starlings flock like this, it’s thought that it throws Peregrines and other predators off the trail. Thousands of birds moving en masse do not present an easy target for a raptor that could otherwise dive on a single victim at over 200 miles per hour.

But, there could be other reasons for this flocking behaviour and as to the psychology of why humans see shapes and animals in the clouds of birds, well, that’s a wholly different story.

While seeing a murmuration on your own doorstep can be quite the spectacle there are even more alluring settings as these birds carry out their coordinated aerobatics in flocks with birds numbers tens of thousands if not hundreds of thousands the world over.

Reports on Twitter of several thousand Black-tailed Godwit, Golden Plover, and Lapwing, several sightings of Short-eared Owl, Peregrines, Wigeon, and Cranes seemed sufficient enticement to take the relatively long drive up to Whittlesea on a bright and very breezy Thursday.

We ended up at not-the-car-park, thought we spotted an owl before we even got out of the car, but it was a Kestrel, and then walked for an hour and a bit along Long Drove towards the dyke that prevents you getting to the little coppice over which the official carpark near Coates looks. No matter we saw birds in large numbers on that walk and then braved the cold a second time at the official carpark where a dozen or more birders with various sizes of scope and lens, mostly green waterproof jackets, black walking trousers and muddy boots had gathered in case the Shorties appeared. None did before we left, although we did see a Barn Owl (Tyto alba) on our way back to Whittlesea

We did see lots of Reed Bunting (Emberiza schoeniclus, male in winter plumage in the top photo of this post), Stonechat (Saxicola rubicola, female above), Fieldfare (Turdus pilaris), Skylarks (Alauda arvensis), and more. And, if not thousands of the aforementioned waders, then certainly several hundred of each, but just three or four distant Cranes (Grus grus), Marsh Harrier (Circus aeruginosus), Merlin (Falco columbarius), Peregrine (Falco peregrinus) (he’s on the fencing in the photo below, ringed, trust me), Sparrowhawk (Accipiter nisus).

Oh, and a closeup Kestrel (Falco tinnunculus) or three.

UPDATE: I should’ve looked in the scientific literature first, but it seems that there really is no genetic basis for a taxonomic differentiation between Carduelis cabaret, C. flammea, and C. hornemanni, or any hybrids and sub-species. In other words, the three “species” of Redpoll (Lesser, common (mealy), and hoary, that we normally talk of as distinct are one in the same species. Lesser = Common = Hoary.

I bought a dedicated nijer feeder for the garden birds, filled it with the requisite seeds and hung it in our beech tree. It took no more than ten minutes for the Goldfinches (Carduelis carduelis) to spot it and start plucking the black seeds from the tiny holes in the metal feeder. This particular design has no perches common with others, perhaps to deter birds that need a perch, but not the Goldfinches one of which found he could be passerine on a nearby twig and easily reach across with his beak.

The Goldfinches will likely take the lion’s share, and these seeds are not cheap (pardon the pun), but not half an hour after I hung it a new visitor to the garden, a species I’d not seen anywhere before – Redpoll (Carduelis flammea (Common) or possibly the almost identical C. cabaret or the subspecies C. flammea cabaret is up for debate) another finch as you might have guessed from its scientific binomial. The bird doesn’t breed in the UK, it is a passage migrant and winter visitor; more commonly seen on the east coast.

Oh, and that red cap, apparently some don’t have red caps (it’s either a dietary or a genetic effect). Read about Goldpolls here.

My usual dog walk takes me along what is essentially a farm drainage ditch (sounds really picturesque, doesn’t it?) and into a local woodland known as Rampton Spinney. However, that drainage ditch, The Cottenham Lode, takes runoff from a vast area of farmland and ultimately follows managed watercourses and spills into The Wash and so is rather important and isn’t quite as municipal as it sounds.

The area supports no small number of birds. Sighted along there and in the woodland in recent weeks and reported by yours truly in these pages on occasion:

Grey Heron, Little Egret, Great White Egret, Green Sandpiper, Kingfisher, Mute Swan, Mallard, Moorhen, Magpie, Bullfinch, Chaffinch, Greenfinch, Eurasian Jay, Magpie, Tits (Great, Blue, Long-tailed), Buzzard (Buteo buteo, pictured above), Peregrine, Kestrel, Red Kite, Wood Pigeon,  Goldcrest (Regulus regulus, picture immediately below), Wren, Robin, Dunnock, Treecreeper (Certhia familiaris, below the Goldcrest), Starling, Blackbird, Song Thrush, Fieldfare, Redwing.

I’m sure there are a few more but that’s the birdlife I recall from the last few winter weeks of walks there. Many of those species, I see every time I walk the Lode and Rampton Spinney. Some not so often. And, of course, summer is a different matter altogether.

Oh, and on today’s walk, overhead, a female Marsh Harrier (Circus aeruginosus, pictured below)