Fledglings and Caterpillars

Some “fledglings” are just too big for the word.

Okay, it’s recently out of its nest and yes it’s doing the wing-flappy thing and calling for its parents to feed it, but it’s just too big and dangerous-looking. For me a fledgling is a small vulnerable thing. Not a harbinger of doom with great big talons.

So I’m going to call it a young Raven.

For the time being anyway. Without hearing their call, I find it tricky differentiating with certainty between Crows and Ravens – particularly when they’re at a distance, which they usually are. There were no distinctive “honk-honk” calls from the adult birds I saw up on the plain a couple of days ago.

I managed to get one or two pictures of the them in flight and although they had longish wings – a Raven characteristic – the tail was not particularly wedge-shaped, which is also a main identifier for Ravens.

I tried to get an idea of the length of the young bird by using the 4 inch fence posts as a scale/guide. By my calculations (treat with caution) the young bird was a bit more than 21 inches long. So if the upper limit for crows is twenty inches, and the lower limit for Ravens is 21½ inches (RSPB guide), that does suggest the young bird was a Raven.

And when you compare the adult bird on the right of the above picture with the young hungry one on the left, the adult is a bit bigger still – more like twenty two inches (using the same method). But then I think the adult was a little closer in this photo so maybe that distorted things. I’m almost a hundred percent but not quite.

[CORRECTION: (posted a few weeks after this post) Glad I didn’t say I was a hundred per cent on the ID. I had assumed the fence posts were 4 inches in diameter as are the barbed wire fence posts alongside our garden, but it turned out they were more like 3.5 inches. Which of course throws out my calculations and makes it look far more likely that they were crows after all. Yet another schoolboy error in my ever lengthening dodgy record of species identification.]

Ravens have been spreading across the country from the West in recent years. I know of one or two other nests not far away (their distinctive “honk-honk” was heard) which have produced young so it looks like another good year for the species. Not all birds have done so well. I learned the other day that a lot of Great Tit and Blue Tit nests have failed this year due to a lack of caterpillars following the record-breaking cold May.

Apparently those parents that did raise young successfully often did so with the help of suet pellets from garden feeding stations. Which ties in with what I saw a few times with the fledgling Blue Tits that I photographed a couple of weeks back.

The bright pink blob turned out to be one of the suet pellets that Chantal had put out on the bird feeder. Apparently they’re made with berry juice which gives them the strong pink tinge.

The nesting season continues. With more insect life about now, current nesters will probably have a better chance of success. I’ve noticed a bullfinch standing guard in an Elder bush on the other side of the field.

He occasional drops down and goes into the brambles where I suspect the female is on their nest. I saw the male goldfinch of the pair nesting in the ivy tree doing a similar standing sentry thing for a while a month or so back. I wonder if it’s a finch thing. They seem so vulnerable to me out on display like that – no shortage of Sparrow Hawks here – but then our Goldfinches survived and raised a brood so it can’t be that bad a tactic.

An upside down Goldfinch Fledgeling feeding on aphids on the willow tree.

I’ve now also spotted a female Whitethroat, and a delicate wee thing she is. I’m guessing she’s partnered up with the male that’s been around for a while now.  She’s even more secretive and cautious than him.

Rare appearance of the shy female Whitethroat, keeping her distance

The male did come close enough the other day for me to get a couple of better photos, but he was still flitting about in amongst the undergrowth, making auto-focusing difficult. Photographically challenging, but beautiful little birds.

Other species seen during the Raven walk included a Yellowhammer and a Stonechat, both singing their hearts out. I’m guessing they were proclaiming their territory or maybe trying to attract females. Whatever, they should have a better chance of success now.

Yellowhammer in full flow
Stonechat contributing to the background twitter of all the other downland birds.

So the unusually cold weather in spring this year had a devastating effect on caterpillars and the bird life that depended on them. But not all caterpillars have had a tough time of it. A couple of weeks ago I noticed an infestation of caterpillars on an Aaron’s Rod plant which had appeared in the gravel by our back door.

I initially thought they might be caterpillars of the Large White Butterfly – they had a similar yellowy green colouring – but it seemed strange that they were on an Aaron’s Rod plant, their normal food plants being of the cabbage family. But as the caterpillars grew bigger and I looked closer it became apparent they were something different. A little research revealed them to be caterpillars of the The Mullein Moth (the Aarons Rod is also know as Great Mullein). Their black and yellow colouring suggests they might be toxic which, I’m guessing, is why no hungry birds picked them off.

Apparently once the Mullein caterpillars have had their fill, they wander off and find a suitable spot to bury themselves and pupate, only reappearing as moths two or three – sometimes as many as five – years later.

After the driest and sunniest spring on record in 2020, and the coldest May on record this year, who knows what kind of a spring will await them.

Fledglings in Dappled Light

Back on April 17th, I took a series of pictures of a pair of courting Blue Tits.

(If you visit the website, rather than viewing on email or the WordPress Reader, you’ll be able to see the below slideshows rather than all the individual pictures.)

The males do a lot of schmoozing, showering the females with gifts – a juicy caterpillar here, a sunflower heart there – and I’d always assumed it was the Blue Tit equivalent of boxes of chocolates and bunches of flowers. But having watched the way the adults feed their fledglings over the past few years, I’ve started wondering whether the female’s approach is a bit more pragmatic than that.

The adult females puff themselves up and flutter their wings in a way that looks very similar to the behaviour of fledglings begging to be fed in the hours and days after they’ve left the nest. 

Could the females be imitating the chicks to see if their behaviour triggers a sufficient feeding response in the prospective male? Maybe they’re checking out the male’s parenting potential before they take the plunge. Doesn’t seem unreasonable: you’d want a male who was good at feeding duties, especially when you could have as  many as ten chicks to look after.

Last Thursday, May 27th, two days short of six weeks since the Blue Tit courtship display, the pair’s progeny fledged. I first realised it was happening when I came outside the backdoor and saw one of the adults perched on the electric cable leading to the house.

He had a juicy looking caterpillar and was twittering in a way that sounded like he was trying to tempt the chicks out of the nest box. I went to see what was happening and I could hear three or four of the fledglings already in the willow tree and there was one in the long grass of the field on the other side of the stream that was calling out repeatedly.

The willow tree, handily positioned for fledglings on their maiden flights

I didn’t see any others leaving the nest box so I’m guessing the rest of the brood – if there were any more – had already dispersed.

Most of the brood were up in the willow tree already.

It can be a bit tricky getting the autofocus to work when your target is in the middle of a tree with branches behind and in front

One fledgling higher up was preening himself thoroughly which was understandable after two or three weeks cooped up in the nest box with all the attendant creepy crawlies.

And then I noticed the fledgling in the long grass fluttering its way up to the lower branches of the willow. It just made it and clung on.

He struggled his way up the dangling branch to a more horizontal perch.

But he was partially hidden behind a vertical branch so I moved a little closer to get a better angle.

The fledgling didn’t seem too impressed by my presence.

A few squeaks and wing flaps later, and one of the parents was down to feed him.

As he perched there, the dappled light shifted as the wind moved the leaves in the branches above, occasional giving the effect of a spotlight trained on him. 

Handsome young fellow
Another one partially in the spot light

Photography gets a lot easier when the subject is on the same level as you and not far away. It’s also handy if the subject is unsure about flying away, unwilling to risk another flight quite yet. It helps too when there aren’t too many branches in front or behind. And when there’s a small puff of wind and dappled sunlight flashes through the leaves for a moment and illuminates your subject perfectly, it’s the icing on the photographic cake.

Of course the fact that the fledglings are clumsy and reluctant flyers does make them easy targets for predators. A few jackdaws landed in the willow tree and looked around for the source of the tweeting. I couldn’t help myself: I shooed them away. And one of the crows saw other jackdaws off as well, as if to say these are my juicy little morsels, not anyone else’s. And then a squirrel turned up. He’d tight rope walked his way along the electric cable that passes through the tree. I know they raid nests and they might just be tempted to go after a clumsy fledgling or two. It was like the bush telegraph had put the word out: easy meals in the willow tree today. Of course we shouldn’t interfere with nature, but then again…

…I shooed him off as well. They’ll have enough time to do their predatory stuff when we’re not around.