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.
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.
First teasing apart of owl pellet
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.
Boney bits and piecesRodent bones after a bit of a cleanupRodent skull next to centimetre scaleRodent jawbonesRodent 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.
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.
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.
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 of 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.
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…
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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 English hroc, and is perhaps onomatopoeic of the bird’s raucous call, which is something of a croak, a word that comes from the Sanskrit “kruc” 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.
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…
Gulls just want to have fun, A gull that can’t say no, Only gulls allowed, The it gull…
A real gull’s gull, Funny gull, Party gull, A daddy’s gull, One of the gulls, Good gull, Cover gull, Gull Friday, The gull next door, Couldn’t happen to a nicer gull…
Little gull’s room, That’s my gull, Working gull, Poor little rich gull, Big gull’s blouse, Call gull, Atta gull, What’s a gull supposed to do?, Guys and gulls…
A slip of a gull, Big gull pants, Old gull, Gull problems, Gull’s time of the month…
Poster gull, Page-three gull, Blue-eyed gull, Glamour gull, Same as the next gull…
Gulls’ night in, What are little gulls made of? Any other gull, Night out with the gulls…
More gulls and other birds and more in my Isles of Scilly gallery on Flickr. There are also my more serious blog posts about IOS with photos.
We went on a pelagic trip in the Isles of Scilly with Sapphire skipper Joe Pender, departing Hugh Town harbour, St Mary’s Island on 9th July 2018 at about 5pm. Within seconds we were being tailed by dozens of Herring Gull.
Engines were cut about an hour out to sea and the anglers aboard began flicking their rods to catch mackerel, which they did, a dozen or so quite quickly. Then the fishing for Blue Shark (Prionace glauca) began. An 83-year old angler hauled in the first (with a little assistance from crew and fellow anglers to get lines around and from under the boat). The catch was a 2.3 metre specimen, it was photographed, scientifically tagged*, and returned to the waves largely unscathed, but perhaps a little confused. I must admit, you could almost see the fear in its eyes while they were doing the weights and measures and shoving the tag under its skin!
Blue Shark, Prionace glauca
The older birdwatchers aboard jeered some of the subsequent efforts. But, by the end of the fishing it was a draw, 6 landed, 6 that got away.
Anyway, the birdwatching, was not quite the numbers game we had hoped for, but aside from the dozens of Herring Gull, we saw lots of Gannet, many over the boat and a distant flock diving on a patch of water where dolphins were also feeding. We had a few Fulmar and about the same number of Manx Shearwater (aka Manks Puffins).
The skipper called out another bird as it crossed our stern and I snapped at it as quickly as I could. I didn’t catch what it was at the time, I thought I heard him shout “Manxie!”. But, back home and on dryland with my laptop I could see it was a Skua that I’d photographed. The Facebook bird ID group called it out – it’s a Bonxie – a Great Skua (Stercorarius skua). Bonxie is a Shetland name for the bird probably a word of Norse origin. Skuas are piratical birds, they will steal food from other birds. But, they’re also predatory, and the Great Skua is capable of killing a kittiwake. Stuart Keenan on that Bird ID group tells me he’s seen one in Wester Ross kill and eat a first-year Great Black-backed Gull! In the same Facebook thread, Mike Honeyman told me that the Bonxies used to have a fairly good crack at the warden team on Fetlar. “We were suitably nervous in their vicinity!” he writes.
So, the Great Skua, a lifer for me, even if I didn’t get a decent shot. I wasn’t quick enough to get a focus lock on this bird as it crossed the stern of our moving boat, when the skipper shouted. The subsequent photos were reasonably sharp as it flew away but underexposed against the bright evening sky as, again, I wasn’t quite quick enough to adjust.
*UPDATE: 2024. The scientific work is important even if a few sharks have to be hauled from the water to be tagged.
The Mediterranean Blue Shark, a species critical to the marine ecosystem, is facing the threat of extinction due to overfishing and a lack of proper conservation efforts. A 2024 study explored the genetic differences between specimens in the Mediterranean Sea and the Northeast Atlantic Ocean to understand if they are separate populations. The results showed subtle genetic differences, suggesting that the Mediterranean sharks are largely isolated from Atlantic populations. This separation means they rely on local populations for survival, with limited new sharks coming from the Atlantic.
This has important implications for conservation. Current management often treats Blue Sharks as a single population, but this overlooks the unique risks facing the Mediterranean sharks. Overfishing in this region could push them closer to extinction, especially since they reproduce slowly and are not being replenished from elsewhere. Protecting these sharks requires more targeted conservation strategies and international cooperation.
This research is vital not only for blue sharks but for understanding how fishing and environmental changes affect marine ecosystems as a whole. Safeguarding such apex predators is essential for maintaining the balance of marine life.
I don’t know if Pender’s tags are specifically part of the data for this particular study, but they do feed into the bigger picture of Blue Shark movements in the Atlantic.
Buzzard (Buteo buteo) takes flight
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