Long-distance Clara

Here's a bird with a little story to tell. This morning I caught a Whitethroat already wearing a ring (a 'control'). The number looked kind of familiar to me so I asked a few other local ringers if it was 'theirs'. It turned out to have been ringed near Tempsford in Bedfordshire, as a chick in the nest, back in June 2010!

When this information is crunched by the BTO, it'll say that the distance travelled between its nest and my place is only about 6km over slightly less than three years.

But in reality, it'll have made the journey from Bedfordshire to sub-Saharan Africa once in autumn 2010, then back the other way in spring 2011 and back again, probably the same in 2012 and has made it back again in 2013. So that's six journeys so far. Each time, it has to fatten up before leaving the UK, make its way through western Europe and through north Africa. For argument's sake, let's say it spends winter in the sahel in Senegal.

If it flew in a straight line directly there (which of course it won't have), that would be a journey of more than 2,700 miles each time. Multiplied by six, that's 16,200 miles! 26,000km!

The oldest known ringed Whitethroat was nearly seven years old, so this one has a way to go to beat that...

Surely not a Wood Warbler...?

I had a bit of a surprise when I stepped outside this morning. Half-asleep, I heard a trill that sounded suspiciously like a Wood Warbler. 

Telling myself it was probably something else that I'd mis-heard, I decided I'd better go and check. It sang again - definitely a Wood Warbler! This wouldn't be particularly noteworthy if I was in mid-Wales, for example, but in Bedfordshire it came as a bit of a shock...

After a bit of searching, I finally clapped eyes on the warbler and later in the day managed a few photos. Wood Warblers don't tend to stop on migration - they prefer to just carry on - but it seemed that it was among quite large numbers of warblers which had stopped off that day.

Painted Ladies

A massive movement of Painted Ladies has been taking place since Saturday. I've heard a guesstimate of 15 million of 'em! Wherever you were at the weekend, it would have been hard to miss them, flying along without stopping, all the way from north Africa.

Where will they end up? How do they know where to stop? Butterfly Conservation want to know where you've seen them.

Two were at The Lodge today in blustery conditions, feeding on Rosemary along with lots of bees.

photos taken with Canon Powershot A640

Ospreys in action

Have a look at Roy Dennis's website for further evidence that migration is a wonderful thing. He's tracking the migrations of three Ospreys which were fitted with satellite tags in Scotland this summer (two chicks and their mother; the chicks were ringed at the nest but the adult female was netted - I'd love to see how!).

The tags are doing their stuff. They show the adult female has made it to her wintering grounds in Senegal, while one of the chicks is now in southern Spain. I've borrowed the graphic showing the female's route across the Bay of Biscay (see above); she made the crossing in about 10 hours.

For the other chick, things didn't quite go as they should have. She took a route south from Scotland to the Isle of Man, then Anglesey but then 'missed' possible stops in Ireland and south Wales.

The tag's last recorded position was north of the Isles of Scilly.

Interestingly, Roy suggests that 'Scottish young have an inherited migration heading, from their Scandinavian ancestors, which takes some of them SSW. This is a good direction for migration from Sweden to Spain, but not so good from Scotland, because of hazardous sea crossings and possible losses in the Atlantic Ocean.'

World Migratory Bird Day

Did you know it's World Migratory Bird Day (WMBD) today (and indeed all weekend)? I didn't.

How do they do it?

9.45pm

Darren is outside in the garden, smoking. A very bad habit indeed, but it has its uses - he's hearing Redwings flying over in the dark!

I think many people associate hearing Redwings' high-pitched 'seeeep' calls with their southbound autumn migration. But tonight came as a reminder that they have to go back the other way, too.

I assumed previously that night migrants such as Redwings would pick a clear night to migrate, assuming that the stars help them plot a course, but this evening it's been drizzling heavily and the skies are 100% cloudy. How on earth are they managing to find their way?

Nobody seems quite sure.

I wonder if artificial lighting comes into it? When coming in to land at a British airport under cover of darkness, you can easily pick out street lights in built-up areas and along major routes, even from quite high up. The Europeans are much better at using energy-saving, light-pollution limiting lights.

Some links to interesting migration-themed features:

• BBC - The mystery of migration
• Science Frontiers - Do birds use genetic maps during migration?
• RSPB - Migration
• BTO - How migration works
• WWT - Swan migration satellite tracking project
• Greenshank.info - Migration Story