Saturday, November 10, 2018

Indoor Post

Looks like I won’t get out birding or ringing for a few more days. To put it mildly, the weather is crap by way of the usual wet and wind. 

But hopefully 2018/19 may turn out to be a “Brambling Winter”, an irruption year for this close relative of the much more common Chaffinch. Migration watch points and Bird Observatories are reporting abnormally large numbers of Bramblings when in more typical years the numbers of Bramblings seen is low in comparison to other autumn migrants and to species that overwinter. 

Trektellen shows a clear spike in UK numbers in late October early November 2018 with three or more days of 2000+ Bramblings at Hunstanton Cliffs, Norfolk and at Spurn Bird Observatory. There are also several days of counts in the high hundreds. 

Brambling 2018 - https://www.trektellen.nl

Brambling 

Brambling 

However, sightings here on the west coast are not nearly as high which is not unusual given that the range of the Brambling is biased towards the east by stretching from Scandinavia and then east through an enormous swath of taiga forest across to Sakhalin and Kamchatka. This area is at the most extreme eastern edge of the Russian Federation at the Pacific Ocean and very close to the northern tip of Japan. 

In "Brambling winters" it is often into the extremes of January and February and icy temperatures before Bramblings find their way to the warmer west coast of England. Such irruptions in a number of birds of Northern Europe most often involve species like Hawfinch, Brambling, Chaffinch, Waxwing, Bullfinch, Siskin, Coal Tit and Crossbill. The common factor is each species’ reliance upon the various seeds of trees found in northern taiga, also known as boreal forest. 

Crossbill 

Waxwing 

These irregular migrations are difficult to study because it is hard to predict when they will happen or where the birds will go each year. In each case, however, irruptions follow some type of boom-and-bust cycle of food sources. It is important to note that many winter birds will gather in flocks for the season, but that does not mean they are irrupting. An irruption is characterized by a distinct shift in the birds' typical winter range, with many birds appearing well outside the normal boundaries of their winter homes. 

Waxwing

The most common cause of this phenomenon is called “masting,” which occurs when a single tree species produces a large number of seeds across thousands of miles of forest in the same year. When the conifers in the boreal forests of Northern Europe experience a masting year, the abundance of seeds gives some species of bird a boost. The birds begin breeding earlier than usual and produce more offspring, resulting in a population boom. When autumn arrives, the bird population has doubled or even tripled, but the available habitat hasn't. Many birds move south, and young birds in particular may be pushed further and farther south and west in search of both food and somewhere to spend the winter. 

Other causes for bird irruptions include unduly harsh cold or severe weather that may force birds to find more temperate wintering grounds, or over-breeding that may deplete even plentiful food supplies. No matter what the cause of the irruption, however, it is difficult to predict where or when irrupting species may appear.

It is known that the Brambling’s strategy during winter, to roost in large dense flocks, is superior to those of other passerines. Also during summer Brambling densities can be very high even at breeding sites when food is abundant. Thus the Bramblings seem to prefer wintering in flocks as large as the available food supply allows permits. 

This may explain why flocks estimated at between 2 million and 5 million Bramblings are sometimes recorded in Scandinavia, Central Europe and Japan. Such flocks can even occur in good years for beech mast, a favoured food of the Brambling. 

Take a look at the video below. At first glance it appears to be a video of a murmuration of Starlings, but in fact all of the birds are Bramblings. The video was shot in Japan, sometime during the winter of 2015/16.  


Back soon with an outdoor post. Until them linking this post to Anni's Blog and Eileen's Saturday.



14 comments:

Wally Jones said...

Very interesting information, Phil, on irruptions and causes. You have now motivated me to do a bit of research. My sister experienced a large amount of tree damage a few years ago on their 100 acres of pine forest due to a hurricane. The forest service told her the force of the wind cause many more pine seeds to be driven into the ground than normal and it caused an unusually high amount of new growth trees the following year.

We may see something similar with the most recent hurricane (Michael) as the area of Florida and Georgia receiving the most damage contains a huge expanse of pine and hardwood forests.

Should be interesting to see what the data reveal. Will check other storm years as well.

Here's hoping your weather improves soon! You need to be outdoors.

All the best.

Rhodesia said...

Your posts are always interesting.

Seeing your header shot reminds me this morning early, I was just driving away from home when what shoots across in front of the car but a Red-legged Partridge!!! Never seen one before anywhere around here and of course, I did not have the camera as I was going for an emergency visit to the dentist!! I did see a lot of starlings as well this evening also something I rarely see around here.

Keep well Diane

David Gascoigne said...

Good afternoon Phil: This year has not been a good year for seed mast in the northern forests and there is little food for the birds that normally remain there, so we expect a substantial movement southwards of numerous species. Already abnormal numbers of Pine Siskins are showing up, and I expect that Purple Finch numbers will soon show a spike. There is a possibility that Pine and Evening Grosbeaks may follow, perhaps crossbills and redpolls. Of course, as you indicate, it is difficult to predict exactly where they will go, but southern Ontario should host some of these birds. The other potential consequence is a movement of northern owls. Less seed means less food for rodents, therefore their populations crash and owls come south in search of food. I have put out a sign that they are all welcome in my yard!

eileeninmd said...

Hello,

I look forward to the years we have the bird irruptions. I have found some lifers during those years, some of my favorites finds were the Redpoll and a Crossbill. Your Brambling is a beautiful bird, love the Waxwing and Crossbill.
Thanks so much for linking up and sharing your post. Happy Saturday, enjoy your day and weekend!

Anu said...

Hello Phil. A lot of interesting information. Thank you.

Adam Jones said...

I do hope that it is a good year for Bramblings Phil. I don't see enough of these birds. Likewise for Waxwings. I hope the weather improves soon so that you can get the ringing nets up. Same weather here, a little further south.

~Lavender Dreamer~ said...

I hope your weather improves so that you can get out. It's finally cool enough here in Florida to be outside more. Love seeing migrating birds...time and chance to see many of them! Have a good weekend!

italiafinlandia said...

The video is amazing! I have seen a Brambling only twice and it was always in April, probably during the south to north migration. Beautiful birds.

sandyland said...

loved this blog post so much

Angie said...

The weather has gotten much colder here, but at least we are getting some sun and very little wind. I have noticed some slight activity at my bird feeders, but the 'locals' are still mainly finding other abundant food sources!

Anni said...

It's been the same here for months, weather, downed trees, less natural food for the birds! Love your portrait of the Bramble & Waxwing!

It's been great to go with you on a birdin' adventure this week from The Bird D'pot, and your charting educational. Thanks for taking us along.

~Lavender Dreamer~ said...

Thank you SO much for helping me with my ID this weekend! I've updated my post again to show that it's a Northern Harrier. I looked at the photos and believe now I've seen a bird I've never seen before...which is very cool! Hope you have a good day!

A Colorful World said...

Fascinating information about the Brambling...a bird I wasn't familiar with! Also loved your Waxwing. Hope you can get out again soon.

Lowcarb team member said...

I do hope the weather improves for you soon …

All the best Jan

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