Birds – Page 21 – David Bradley

Knots Landing

They’re naming the new hide at RSPB Snettisham “Knots Landing” in honour of the bird,Â Calidris canutus, that flocks in vast numbers in and out over The Wash there with each turning tide.

The bird is named for King Canute (it’s not a long way from ca-nute to k-not and then dropping the k, in Dutch they’re called “Kanoeten”) because theseÂ medium-sized waders, which breed in theÂ tundraÂ and theÂ Arctic Cordillera ofÂ Canada,Â Europe, andÂ Russia will whoosh from the mudflats and sandbanks as the tide rises until they are ankle deep at high tide periodically forming vast flocks that shapeshift across the skies.

We visited on the third weekend of October 2018, catching the late afternoon high tide on a clear day that ended with a glorious sunset and seeing flocks of several thousand Red Knots. There were a couple of thousand Oystercatcher there too and perhaps 1000 or so Golden Plover, not to mention the hundreds and hundreds of Pink-footed Geese that leave behind their feeding grounds and head out to sea to roost at dusk safe from terrestrial predators.

Sometimes entangled in your own dream…knots…you can find the non-avian sunset photos on my Imaging Storm site.

Avian ancestry

Our feathered friends, the birds, are all descended from the dinosaurs. Specifically, birds evolved from the hollow-boned theropod dinosaurs which includes the Tyrannosaurus rex. All 10500 species of bird alive today and all the many thousands of others that are extinct came from the dinosaurs. But. Didn’t the dinosaurs die out 65 million years ago when a huge asteroid hit the Earth, you ask? Well, most groups that were still around at the time did, allowing the mammals to fill the ecological niches left empty by their sudden absence. However, the lineage of those hollow-boned dinos would persist too. The question is how did they survive when their cousins died out?

Writing in the journal scientists affectionately know as PNAS, researchers explain how they have found another adaptation that could have given the ancestor of the birds an advantage when things got very tough for the other dinosaurs. They have examined the fossilized lungs of a bird ancestor, Archaeorhynchus spathula, using scanning electron microscopy and found features in the lungs of those animals that resemble those of modern birds and are thought to be an evolutionary adaptation that supported flight include unidirectional airflow in the lungs, supplementary air sacs, and lung tissue that is finely subdivided to maximize surface area and so absorption of oxygen from the atmosphere to drive the huge energy requirements of flying.

Crocodilians are the only other living creatures that have unidirectional airflow and this characteristic is now thought to have evolved even before the ancestors of the early feathered dinosaurs.

The authors also discovered among the preserved plumage of the fossil a pintail feather structure that has not been seen in other known birds of the Cretaceous period but is seen in some modern birds. The researchers suggest that all of this evidence stacks up to the fact that key avian structures were in place by the Early Cretaceous and could have been what helped the ancestors of modern birds survive the extinction of the other dinosaurs.

“Archaeorhynchus preserving significant soft tissue including probable fossilized lungs,” Xiaoli Wang et al. Proc Natl Acad Sci (2018)

RSPB Ouse Fen

I’m always hopeful of interesting sightings along The Reedbed Trail at RSPB Ouse Fen. Saw lots of Hobbies and Terns as well as Marsh Harriers and Warblers there earlier in the year.Visited today with Mrs Sciencebase, two or three Marsh Harriers in evidence, lots of gulls, a single Kestrel, one or two Buzzard, big Lapwing flock, Grey Heron, waterfowl, Little Egret, Goldfinch, Reed Bunting, Green Woodpecker, Stone Chat pair, and the pew, pew, pew sound of Bearded Reedlings of which we saw a few but didn’t get any great shots. But, at least confirmed what I thought I heard earlier in the year and nice to know they’re colonising a local reserve. Oh, and as we were leaving, we saw a fox, other visitors with dogs unwittingly scared it into the trees.

Buzzard (Buteo buteo) takes flight

Female Reed Bunting (Emberiza schoeniclus)

Mrs & Mrs Stonechat (Saxicola rubicola), RSPB Ouse Fen, VC29

Bearded Reedling wouldn’t turn to the camera before flying off!

Goldfinch alighting on barbed wire fence at RSPB Ouse Fen

Some of a flock of 500 or so Lapwing over RSPB Ouse Fen

Barn Owl pellet

TL:DR – Barn Owls regurgitate pellets containing the indigestible bones and fur from their prey. It is possible to dissect these owl pellets and to find out what the owl has eaten from the debris.

Barn Owl (Tyto alba) hunting over Rampton, VC29If you have ever stopped to think about the gustatory habits of owls, then you have perhaps wondered what happens to all the bones and fur from the little creatures on which they predate after they eat them.

Dry Barn Owl pellet, obtained from WWT Welney

Well, avian digestive enzymes do not have the capacity to break down bones and fur and as the flesh and organs are digested those materials accumulate in the upper gastrointestinal tract forming a hairy bolus, a pellet, that ultimately the owl will regurgitate. A pellet forms after six to ten hours following a meal in the bird’s gizzard, its muscular stomach. Owls and other birds of prey bring up the indigestible material from the proventriculus, their glandular stomach. The pellet is thought not only to get rid of indigestible waste materials that would not pass downwards safely but also to scour parts of the digestive tract, including the gullet to remove detritus that might harbour pathogens.

Single fragmented owl pellet soaking in water

Now, the experimental bit.

I collected an owl pellet (with the warden’s permission at WWT Welney on a recent visit and followed his instructions to soak the pellet in water for a number of hours and then to tease it apart to reveal the bones within its proventriculus, or glandular stomach.

After about an hour’s work I’d dissected the pellet to reveal a relatively large skull and separated lower jawbones of presumably a vole as well as various femurs, tibia, fibula, scapula, a few vertebrae and lots of rib bones, and perhaps another couple of much smaller skulls the extraction from the of the pellet I did not have the patience nor the equipment to pursue with the necessary care and attention to detail. I did not find any feathers nor insect exoskeletal parts or wings in this pellet. All the remains were rodent mammal.

Rodent (vole?) mandible next to skull extracted from owl pellet

Anyway, I am quite pleased with the produce harvested from my first owl pellet dissection. Mrs Sciencebase points out that she did the very same experiment as a biology student many moons ago.

Rodent lower hindlegs – tibia and fibula

Other birds, including the fish-eating, insect, and carrion-eating birds, grebes, herons, cormorants, gulls, terns, kingfishers, crows, jays, dippers, shrikes, swallows, and most shorebirds also produce pellets.

Cranes at WWT Welney

UPDATE: Just over 5 years later, night of 7th November 2024, 83 Cranes into roost at Welney.

There is a flock of 37 Cranes (Grus grus) at WWT Welney in Norfolk at the moment. Some of these have bred on the reserve, all of them, it seems, share their time between this site, NT Wicken Fen, Kingfisher’s Bridge Nature Reserve, RSPB Lakenheath, and the Ouse Washes.

Photos were taken from the Visitor Centre viewing platform, fully zoomed (600mm on a full-frame SLR) and cropped. The birds were about 900m away so the photos are not particularly distinct.

European Robin – Erithacus rubecula

It occurs to me occasionally and I forget to mention it, that this is probably the species of bird we Brits probably picture when we hear the song Rockin’ Robin.

I suspect, however, that the guy who wrote the song, Leon René (aka Jimmie Thomas), was actually thinking of the American Robin (Turdus migratorius), which is like a British Blackbird (T. merulea) or a Song Thrush (T. philomela) but with a red/orange breast.

Anyway, the American Robin’s song is much closer to the refrain “Tweet, tweedle-lee-dee” in the hit, than the rambling and melodic song of the European Robin. One more thing, check out the cover artwork of the record by original Rockin’ Robin artist, Bobby Day, he’s got macaws, parrots, but no sign of a Robin, American, European or otherwise as far as I can see.

Now, here’s a thing…mammals have a single set of vocal folds in the larynx of their trachea. That means they can only really ever bark, moo, yelp, or sing with one voice using that set of vocal folds. The “voicebox” of birds is further down their pipes at the place where the trachea branches into two bronchi. Birds have a syrinx* rather than a larynx, which allows them to create two tones at once.

The European Robin (Erithacus rubecula) is an old world flycatcher. Like I say, not to be confused with the American Robin demonstrating what is possible with a syrinx. Listen out for his neighbours calling at the points in the video when he stops singing. It’s impossible to know who sang first, maybe he’s replying, or maybe it’s them calling back to him.

For Rush fans, yes, that is the reference! The Temples of Syrinx from the 2112 opus. In classical Greek mythology, Syrinx was a nymph and a follower of Artemis, the goddess of the hunt.

Syrinx was known for her chastity, making her the perfect object of worship for the Priests of the Temples of Syrinx who by the year 2112 have banned pleasure (specifically music played on guitars) from the world in deference to computers. In Greek mythology Syrinx was pursued by Pan, the god of the wild and music.

To evade his advances, she fled into the river Ladon, where she asked the gods to turn her into reeds. Pan, of course, took those reeds and from them fashioned his panpipes, ultimately possessing Syrinx for his own pleasure. This myth is why the word syrinx is used for the double vocal flute of birds.

More from RSPB Lakenheath

A few more snaps from the photography station and visitor centre at RSPB Lakenheath:

Great Spotted Woodpecker (Dendrocopos major)

Lakenheath Revisited

We visited RSPB Lakenheath for the first time back in snowy February. They were just setting up a photography hide with naturalistic perches and feeders and a reed bed for Bunts, Tits, Kingfishers, and the like. In fact, first shot I got there was of a beautiful Kingfisher who popped in stared at the camera and disappeared within the space of about ten seconds. This visit, we had numerous Tits (Great, Blue, and Marsh), Reed Bunts, Goldfinches, and a few others, and a male Great Spotted Woodpecker, but did no spotted Kingfisher at this site this time.

Below Little Egret (Egretta garzetta)Â fishing

Great Tits (Parus major) feeding

Reed Bunting (Emberiza schoeniclus) bunting

Juvenile Goldfinch (Carduelis carduelis) just starting its facepainting

There were plenty ofÂ caterpillars of Aglais io, the European Peacock, writhing on a nettle patch near New Fen Hide at RSPB Lakenheath. They are late, as this species usually lays eggs in June from which caterpillars soon emerge. Despite their defensive spines, many of them are eaten by parasitic wasps.

Meanwhile, we also saw all three of the site’s celebrity spiders: Wasp Spider, Crowend Orb Weaver, Marbled Orb Weaver. More about those in this post. But missed the Common Heath butterfly (plenty of Small and Large Whites, and one Comma).

The Toadflax (Butter and Eggs plant, Linaria vulgaris) was dying off but there were a few flowers still in bloom

There were countless airborne dragonflies and quite surprising not to see the local Hobbies (Falco subbuteo) chasing and eating this fast food supply, especially those distracted by their mating rituals.

More snaps from today’s trip to RSPB Lakenheath here.

Rooks, rooks, croaks, and crooks

I always assumed that the chess piece we know as a “rook”, which resembles a castle was named for the bird, there being some link with ravens in towers and turrets, perhaps.

But, it’s nothing of the sort…

The word was coined around 1300 and comes from Old French “roc”, which in turn comes from the Arabic “rukhkh”, and that from a Persian word “rukh”, which may in turn come from the Indian name for the piece, “rut”, from the Hindi “rath” meaning “chariot.”

Of course, if I’d known my chess history, I’d have known about the mediaeval game “shatranj” where the rook symbolizes a chariot. But, it might also represent a siege tower after that. The original Indian game had chaturanga meaning also meaning chariot, but the modern version of that game calls those pieces “elephant”. Some people call the rook a castle and “castling” is a chess manoeuvre involving two pieces (king and rook) swapping relative positions in a single move. Does any of that have anything to do with the name of the old coaching inn, “The Elephant and Castle”, for which the area of South London is named? Probably not. Although the E&C statue is of an elephant carrying what looks very much like a chess rook on its back and that is an early gaming piece in chess evolution.

Anyway, he name of the bird, on the other hand, the Rook, comes from Old EnglishÂ hroc, and is perhaps onomatopoeic of the bird’s raucous call,Â which is something of a croak, a word that comes from the Sanskrit “kruc”Â meaning to cry out. Moreover, a rook is a 16th century word for someone who cheats at cards or dice. The word “crook” itself, which you might think is somehow related, was originally a word specifically for a devilishly dishonest trick.

Of course, a word that was bandied about a lot during the US presidential elections was “crooked”, a term pertaining to someone cheating, but also simply meaning bent as in a shepherd’s crook. But, the word bent also means crooked in both senses, but someone hell-bent is determined to get what they want, perhaps by hook or by crook.

Don’t you just love etymology?

Science, Snaps, Songs…Birds

I have attempted to categorise and separate out the science, snaps, songs, and birds posts, so that you can focus on just one subject, there is lots of overlap. For example in a post about research into a particular species of bird where I have illustrated it using my own photos or in a song with lyrics inspired by a scientific principle or discovery, again where I may have illustrated the post with my photos (birds or otherwise). Hope it’s useful…

David Bradley’s Songs, Snaps and Sciencebase.com