Category: Biology

Older male birds father more illegitimate offspring than younger birds, it seems. When female birds have chicks as the result of an “extra-marital” fling, the fathers are almost always older males. Now, scientists at Imperial College London think they know why.

Many birds form social pair bonds, some of which last a lifetime, but they may also have “illegitimate” offspring. Extra-marital copulation in sparrows seems to favour paternity of older males and there were two possible explanations: older males are better at coercing females into extra-pair affairs, this is the male manipulation hypothesis or that females solicit more sex from older males than from younger males, the female choice hypothesis.

Sparrows are socially monogamous but sexually promiscuous, staying with one partner for the security of raising chicks, but with the males not necessarily raising their own chicks. The team led by the IC scientists observed more than 450 mating attempts by males, and found that older males did not try to make females cheat any more often than younger males, which throws the male manipulation hypothesis into doubt. Instead, they observed that successful affairs were more often solicited by females. However, the females did not choose older males more often than younger males, suggesting the female choice hypothesis may also be wrong.

Team member Antje Girndt explains, “There is a difference between what we observe and what the outcome is: we didn’t observe older males cheating more often than younger males, but they do father more offspring. This suggests there is another factor at work, such as older males having more competitive sperm.” Females can store sperm for weeks before allowing it to fertilise their eggs.

“We found that there is likely to be a biological effect, rather than a behavioural one, for why older males are more successful at siring illegitimate children,” explains research leader Julia Schroeder. “It has been thought that females might choose older males as they are more ‘genetically fit’, but our research casts some doubt on this.”

http://doi.org/10.1038/s41598-018-26649-1

It seems I have landed myself the entirely voluntary role of writing the bimonthly Bird Report for our local newsletter – Cottenham News. The column has been expertly and diligently handled until now by local birder Jasper Kay, but times move on and he has handed over the reins to this very amateur birder. Anyway, I’m not going to try and follow in Jasper’s footsteps but will attempt to put together a regular bird column with a sidebar that cites local sightings in, over, and around our patch.

Bird Report 1 – What’s a warbler, anyway?

Seasons come and go and so do many of the birds we see at different times of the year. Those that spend the summer, we call summer visitors. Many of them travel thousands of miles from Southern Africa or elsewhere to be with us during the summer: the cuckoos, swallows, swifts, and house martins. Perhaps less familiar is a group of birds we call the “warblers”. Warbler refers to a very disparate group of small perching birds that are really only united in that you might refer to the songs and call as warbling, although some of them are less melodic than others and more scratchy avant-garde improvisers, that’s probably too unwieldy a name for a type of bird.

Walk along the Cottenham Lode and you might catch a fleeting glimpse of a cackling bird with a white throat, which goes by the rather obvious name the whitethroat (Sylvia communis), you might also see its more furtive cousin the lesser whitethroat (Sylvia curruca). Among the more avant-garde of the warblers, is the reed warbler (Acrocephalus scirpaceus), which again rather obviously, as its name suggests, is a warbler that lives among the reeds.

Head into the Rampton Spinney and you might hear the summery and rather more melodic song of its cousin, the blackcap (Sylvia atricapilla). A grey bird with, yes, a black cap. Unless it’s the female or a youngster in which case the cap is a chestnut brown. You may well have had blackcaps over-wintering in your garden during the last few years. Tracking of specimens from Eastern Europe would suggest that many get lost when heading back to North Africa and Iberia for the winter and find our bird feeders enticing and that our generally reasonably warm winter climate suits them fine.

During the summer months, you might also hear the regular chiff-chaff call of the chiffchaff (Phylloscopus collybita). This species looks almost identical to the willow warbler (Phylloscopus trochilus), which, bucking the obvious naming trends, does not only favour willow trees. Both birds are small and variously hued in browns and yellows. The chiffchaff has dark legs whereas those of the willow warbler are pink and the latter has longer wings. However, the most notable difference is in their song, the willow warbler preferring a descending fluting melody over the chiff chaff’s rhythmic cadence. That said, leg colour can vary and some specimens will on rare occasions mimic the other species in their song, so there is rarely 100% certainty in their identification.

It is on local nature reserves rather than farmland that you are more likely to see some of the other warblers including the noisy and melodic Cettis’ warbler, the flighty sedge warbler, and the grasshopper warbler with its talent for mimicking the sound of, you guessed it, grasshoppers. You might have to head to Dunwich Heath if you want to see the troubled Dartford warbler and perhaps even further afield to see a marsh warbler, moustached warbler, Bonelli’s warbler, or the fan-tailed warbler.

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Recent sightings in and around Cottenham Marsh harrier, red kite, buzzard, kestrel, little egret, heron, corn bunting, meadow pipit, skylark, yellowhammer, over and around local farmland and waterways Whitethroat, lesser whitethroat along Cottenham Lode Blackcap, green woodpecker, great spotted woodpecker, willow warbler, chiffchaff, bullfinch in Rampton Spinney Unconfirmed bluethroat (on Brenda Gautrey Way), Turtle Dove along the Lode.
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The title of this post paraphrases Francis Healy in the Travis song “Writing to reach you” where he is presumably having a sly dig at elderstatesmen of BritPop, Oasis and their song “Wonderwall”, presumably with at least a nod of recognition to the 1968 psychedelic film of that name with soundtrack by George Harrison.

Towards the end of February I was lucky enough to catch sight of the Cambridge Peregrines in town and snapped a few shots of the female before the male arrived and mated her. Today, we saw the female preening on the shady side of one of their habitual towers. I got a few low-light shots of her and then spotted feathers cascading down from the sunny side of the tower. It was the male plucking a pigeon high up, basking in the sun as he did so, and once the job was done, he flew off to the nest site and began feeding pickings from the carcass to his two chicks.

It’s astonishing how few people even look up as they walk past these ancient Cambridge buildings. Perhaps they are not interested in the possibility that a pair of large falcons is just above their heads. Nobody even asked what I was zooming in on. Maybe they thought I was simply recording details of the sandstone architecture.

There is another pair just outside town, which I also photographed recently.

 

For me as a kid, you couldn’t beat a good space book, if it was stars and planets and the almost science fiction world of the Space Shuttle (in the early 1970s it was still a dream). I say that but a good shark book would come close, or better still one that had dolphins and whales too. Then again, one with magnets and motors, circuits and pulleys might occupy my time and at least in my pre-teens I had a chance of playing with magnets, but not swimming with dolphins. But, if I remember rightly, those subjects were not the top of the list. Dinosaur books were the top of the list.

Landing on my desk today is Steve Brusatte’s latest tome and it goes by the rather enticing title of “The Rise and Fall of the Dinosaurs: The Untold Story of a Lost World“. What more could my pre-teen self want? Well, admittedly it is mostly words and far fewer pictures than I would’ve preferred at that age, but these days I can cope with lots of words. Brusatte is one of the world’s leading palaeontologists and he evolves the engrossing story of the rise and demise of the dinosaurs from the dominant place in life on earth to their end 66 million years ago.

Of course, Chapter 8 reminds us, to my delight and my current sciencey preoccupation, that the dinosaurs never really went away. Indeed, the descendants of the theropod dinosaurs of which Tyrannosaurus rex is perhaps the most famous and infamous example, are alive and well to this day and flapping their feathered wings all around the world. All ~10,500 species of them…the birds.

Brusatte has discovered and named 15 new species of dinosaur and led groundbreaking (literally?) studies of the rise and fall of these animals.

There were reports of a migrant Spoonbill on passage at RSPB Ouse Fen (Needingworth, Cambridgeshire). So, first day after the rains, I went looking. Didn’t see any Platalea leucorodia (had seen a pair at RSPB North Warren, Aldeburgh, in May 2017 though). However, the Whitethroats (Sylvia communis) were out in force (usually arrive 2-3 weeks after the other warblers) as were the European Green Woodpeckers (Picus viridis).

There were also lots of Chiffchaff, Blackcap, Willow Warbler (all seen and heard) and Reed and Garden Warblers (heard but not seen), a Wren, Jay, Little Grebe, Grey Heron, Robin, Long-tailed Tits, a couple of Buzzards (Buteo buteo).

I didn’t sight the Marsh Harrier one fellow walker had seen. But, there was also a Turtle Dove turring in a grove and a Cuckoo cuckooing somewhere on the patch. Saw neither. However, I did see a Cuckoo perched on an overhead wire on the drive home, just outside Rampton.

The Mute Swans and Coots are still on their nests, but the Canada and Greylag Geese are chugging around the lakes with goslings in their flotillas now. No terns, but several Swallows, a couple of Housemartins, and my first sighting of the year of a Swift (Apus apus)

Above photographs by David Bradley in order from top to bottom:

European Green Woodpecker
Chiffchaff
Canada Geese and goslings
Swift
Whitethroat
Coot
Mute Swan
Greylag Geese and goslings

A vast drinking water reservoir in the English county of Rutland, about half way between Peterborough and the home of the pork pie, Melton Mowbray, is home to the first Western Ospreys (Pandion haliaetus) to breed in England for 150 years. A translocation programme means that these raptors are now breeding at Rutland Water having been settled there, migrated (naturally) to Africa (Senegal, the tracking devices show) and then returned in the spring.

In paying the birds a visit, we made the mistake of heading to the Wildlife Trust’s Rutland Water Nature Reserve in Egleton, near Oakham, paying our money (to a worthy cause, of course) to get on to the reserve only to be told that the nest site was way over the other side, a three-mile walk in fact. Well, we made the best of the visit and took in a short walk on the Reserve and could just about see the female on her nest from one of the hides, but she was far too far away and I was disappointed to not get a good shot even with a 600mm zoom.

Other visitors we spoke to during our walk though mentioned having “fallen for that” entry fee trick before (there is public access and public footpaths aplenty around the reservoir). They suggested heading back out on to the main road in the car and parking up near the railway viaduct at Manton. We did so and could see the male perched not far from the nest on a dead tree branch protruding from the water. He was still some distance away, so not a great shot, but half the distance at which I had attempted to photograph the nest from the Reserve itself. The female could be seen occasionally bobbing and turning her head on the nearby nest.

The project has a live webcam over the nest, so you can get a good close-up view of the birds, which at the time of writing are brooding three eggs, I believe. The female is called Maya and the male has the name 33. I just browsed to the webcam and saw the 33 arrived to relieve Maya from brooding duties, presumably so she could get some food and exercise, here’s a screen grab from the webcam

Looking something akin to a small, tree-surfing kingfisher or a tiny woodpecker, the acrobatic Nuthatch (Sitta europaea) will scoot up and down the bark head first, in a manner unlike any other bird. Certainly it doesn’t creep endlessly upwards like the Treecreeper.

The Nuthatch will pluck small insects and grubs from the bark of trees for food, but will also find seeds and kernels and wedge them in a crevice smashing them open with its beak, hence the hatching of nuts from whence its name originates. It has a variety of calls from a pew, pew, pew to a pwee pwee, by way of a ka-ka-ka.

You will see them on garden bird feeders and often hanging around the visitor centres of nature reserves, anywhere with an abundance of insect life, decent craggy-barked trees, and a seed supply.

UPDATE: Report of cuckoo in Cottenham, at Fen Drayton, and at Paxton Pits last day or two.

Cuckoos tracked by the BTO have returned to Old Blighty, a couple of days later than last year.

Mrs Sciencebase and I have seen several of the UK’s regular summer visitors during the last couple of weeks (Blackcaps, Martins [Sand and House], Swallow, Willow Warbler etc) but we have not heard nor seen any Cuckoos this year yet.

Listen out for this brood parasite with its unmistakeable call. We saw and photographed two males in May 2017. The mostly grey-coloured bird looks a bit hawkish but a lot smaller than most raptors. Also comes in a rufous coloured variety (caught sight of a rufous cuckoo on the North Norfolk coast in the summer of 2017.

Druridge Bay is a pristine stretch of golden sand in Northumberland nestled between the settlements of Cresswell at its south end and Amble to the north. Commonly, there are plenty of seabirds around, various gulls, Sanderlings, Dunlin, Oystercatcher, Cormorants and more. Among the dunes, you will see and hear Meadow Pipit, Reed Bunting, Skylark and more. But, head ever so slightly inland across the dunes and the main road and you will reach a watery wildlife reserve that was once an open-cast mine where there is now an abundance of waterfowl: Curlew, Black-tailed Godwit, Redshank, Lapwing, Grey Heron, Shoveler, Mallard, Avocet, and many others. On our visit (14th April 2018), there was also Ruff, Pintail, Red-breasted Merganser, and various others.

Hunting Heron (Ardea cinerea)

Red-breasted Merganser (f) splashing about (Mergus serrator)

Red-breasted Merganser pair

Ruff preening (Calidris pugnax)

Crowd of Curlew (Numenius arquata)

Black-tailed Godwit take fright and flight (Limosa limosa)

Bedraggled female Linnet (Carduelis cannabina); male Stonechat (Saxicola rubicola) behind

Skylark showing his crest well near Cresswell (Alauda arvensis)