Saturday, 18 November 2017

Bird of the week - Hawfinch

Hawfinches are shy and elusive birds so I was very pleased to see these near Morpeth.  In the winter they eat tree seeds and are very fond of hornbeam seeds.  These birds were in a row of mature hornbeams on the site of an old tree nursery.  Hornbeams are not native to the north of England but there are mature trees which have been planted in parks and gardens.  The birds I was watching mostly appeared in the tops of the trees for a few moments before disappearing so all the photos are at long range and heavily cropped.

The most striking feature of the hawfinch is its enormous bill, used for cracking open seeds and fruit stones.

The male's colouring is beautiful but catching a well coloured male in good light was difficult.  This one wouldn't sit in full view but you can see the colours on his head and the blue in his wings.  You can see how well he is camouflaged against the hornbeam leaves.

A lot of the birds were less brightly coloured - probably females or this year's young.

Even in silhouette they are pretty easy to identify.

The hawfinch is Coccothraustes coccothraustes, meaning kernel breaker.  Few of the birds I saw stayed for long but this one was feeding on the hornbeam seeds for a few minutes.

The hawfinch is a scarce breeder in the UK with fewer than 1000 pairs.  Numbers have declined markedly over the last thirty years and it is now red listed.  This map from the BTO Bird Atlas shows it is mainly confined to a few areas of the country.

The winter population is a little higher and more widespread, boosted by migrants from Europe.

This autumn has seen a record influx of hawfinches.  This graph from BirdTrack shows a reporting rate 12 times higher than the historical average.  Lets hope a few of them like it here and decide to stay and breed next year.

There are plenty of hawfinches in continental Europe so it is a bit of a mystery that they are so rare in the UK.  Causes for their decline here include habitat loss and predation of nests by American grey squirrels.  This EBCC map shows the European distribution.

And a graph from EBCC shows a stable European population.

Thomas Bewick made this engraving of a hawfinch for A History of British Birds (1797).

Archibald Thorburn painted this male hawfinch along with male and female linnets.

You can listen to the BBC Radio 4 Tweet of the Day on hawfinches here.  To learn more about hawfinches and their rise and fall you can read a great article by Ben MacDonald in Birdwatching here.

Thursday, 16 November 2017

Stocking up for winter

At this time of year jays are very common in the garden.  From September I can hear them screeching in the tops of the oaks, where I presume they are collecting acorns.  By November many of the acorns have fallen and the jays collect them from the ground.  This one was picking them up and burying them in the lawn, only a few metres from where it found them.

Jays bury acorns to store them for the winter and this process is thought to be the main one by which the oak spreads its seeds.  Oaks don't usually regenerate in established woodland as they are out-competed by other faster growing trees.  Jays prefer to bury their treasure in more open settings such as scrub or grassland.  It has been estimated that a jay may store as many as 5000 acorns in a season and may travel more than a mile to bury them.  It will remember the position of most of them and recover many of them but those that are missed have the opportunity of growing into oak trees.

Monday, 13 November 2017

Mrs Otter gets the breakfast

It was a cold dark morning and I nearly decided to stay in bed.  I am so glad I didn't as I ended up with the most thrilling encounter with the otters so far.  When I got to the hide just before sunrise there was no-one else there (always a good sign).  I peeped through the shutter and could see an otter in the pool.  When I got the shutter open I could see there were two as they climbed onto the far bank.  The light was very poor as the sun was not yet up (please excuse the photos).  The otter on the left has a fish and I am pretty sure it is a pup and the other behind it is the mother.

The mother otter got back in the water and a few minutes later caught another fish.  She climbed out again, a bit farther along the far bank and again followed by a pup, and left the pup to eat the fish.

She got back in again and at this stage it dawned on me that there were still two otters in the water (the first one had finished its fish), so three in all.  Mother was doing more fishing and the otter pups were surfing like porpoises their excitement.

This is the closest I got to a photo of all three - the two pups are swimming towards me and the mother is diving just behind them.

She then caught another fish and climbed onto the bank just below me with one of the pups and again left it to eat the fish.

A few photos of the pup.  It was partly hidden by the grass and kept looking the wrong way while it was eating but in the fourth photo you can see the tail of the fish about to disappear. 

Mother wasn't finished yet.  She caught another fish and again gave it to the other pup in the corner of the far bank.  At this stage both pups were on opposite banks eating their breakfast.

In the 25 minutes or so that I was watching the mother otter caught four fish and gave them all to the two pups. Eventually they all moved off to another part of the lake.  It's days like this that make up for all the quiet times in the hide when nothing much seems to happen.

Saturday, 11 November 2017

Starlings on defence manoeuvres

Our local starlings are putting on a dazzling display every evening.  The murmuration has a purpose and is not just for our benefit or for the starlings' enjoyment.  This type of behaviour has parallels with the shoaling of fish or the herding of mammals and is a defence strategy.  It is an emergent behaviour, that is it arises from the combined effect of individuals following very simple rules without any central coordination.  The starlings do it as a defence against predators, in this case against sparrowhawks.  The beauty of it all, to our eyes, is a by-product.

It has been exciting to watch the sparrowhawks trying to catch their dinner.  They appear soon after the first starlings arrive over the reserve, shortly before sunset.  Here you can see one sparrowhawk flying close to the murmuration (top right) but the starlings are well aware that it is there and can't catch them.

This is probably roughly a sparrowhawk's eye view of the murmuration as the starlings fly over the hide.  The predator is disorientated by the numbers and movement and can't lock onto a target.

The experts' assessment of the numbers this week is 25-30,000.  The noise as they fly overhead is like surf on the shore and we can feel the downdraught from their wings as they fly by close to the hide.  The starlings' aim is to get down into the safety of the reedbed as fast as possible and they seem to pour out of the sky.

Thousands upon thousands vanish into the reeds in seconds until you would think there wasn't room for any more.

The sparrowhawks have changed strategy by this time and skim over the reeds, hoping catch a starling unwisely putting its head up.  At this stage it is nearly dark so the photos are poor quality but at least you can see what is happening.  Modern camera sensors are good but not as good as a human eye.  Presumably a sparrowhawk's eye is even better.

If they fly against the sky the camera has a better chance of focussing.

The hunters dash back and forth as the starlings continue to pour into the reeds but we didn't see one caught.  By the time we left all the birds were down in the reeds and it was almost completely dark.  This view into the reeds shows the birds drinking and bathing, even as latecomers arrive above them, so they look fairly relaxed.  One sparrowhawk dived into the reeds as well and didn't reappear so I don't know whether it managed to catch its supper.

To give you an idea how dark it is, here is an unprocessed version of the photo above, the best the camera could manage, even with an ISO of 12,800.

I have also seen the birds leave in the morning, before sunrise.  There is a very loud chattering noise in the reeds and suddenly they all take off in unison with a roar of wings.  They fly fast and very low over the reeds and skim the trees, looking like smoke pouring from the reeds.  They were again pursued by the sparrowhawk, this time looking for its breakfast.