Making It Count

“Don’t count the days. Make the days count” - a quote from the greatest boxer of all time Muhammad Ali. 

On that basis I rose at the unearthly hour of 0530 on Friday to meet up with Andy out Pilling way to once again set up mist nets in the half-light of 3° where cold fingers fought to stay warm.  With no time for chitchat our priority was to set nets in readiness for early birds in search of a worm or two, hopefully Redwings. As the morning progressed we expected to add more species and numbers. 

Although we have both seen and caught numbers of Redwings this autumn, the strange weather of the last three weeks has seen very few Fieldfares to accompany their cousins. The two thrushes often arrive together in mixed flocks of tens, dozens, hundreds or even thousands, but not this year. Perhaps Friday would see both arrive as dawn broke or soon after? 

There were no Fieldfares again so we made do with three Redwings that found the net in the dark. Those were the only ones we caught out of 40+ that flew over in tiny groups in three hours and more. 

The morning continued with a light drizzle out of the 100% grey cloud and poor visibility, murk that hung around for quite a while and prevented us from any useful birding. The light was so poor that my camera stayed in the car, these pictures from previous days.

The most notable thing about Friday morning was how the highly mobile Linnets reached approximately 200/250 individuals, a number reflected in our catch of 21. This brings the total of Linnets ringed here this autumn/winter period to 192 - with zero recaptures. If only we could persuade more NW ringers to target Linnets we might together discover more about this Red Listed species. 

New birds caught: 21 Linnet, 3 Redwing, 2 Greenfinch, 1 Wren, 1 Long-tailed Tit, 1 Blue Tit and 1 Reed Bunting. 

Redwing

Linnet

Greenfinch

Reed Bunting

News arrived of a Lesser Redpoll, Ring number AKE3924, a second year female we ringed up at Oakenclough back on 19 March 2020. 

AKE3924 was recaptured over the Pennine Hills by other ringers in Spennithorne, North Yorkshire on 20 October 2021, a duration of 586 days and a distance of 73 km. 

This is another between years Lesser Redpoll recovery that tells us little except that both dates coincide with known migration times of Lesser Redpolls and also their north/south and south/north movements in spring/autumn. 

Lesser Redpoll - Oakenclough, Lancashire - Spennithorne, Yorkshire

Lesser Redpoll

We live to ring another day but probably not this weekend when the weather again turns unfriendly. 

The whole of next week looks reasonable in which to make our bird ringing and bird observations contribute to the wider picture. Log in then to Another Bird Blog to see how we do.

 

Up There. Somewhere.

Migration, the regular movement of birds and wildlife from one part of the world to another and back again is one of the wonders of the natural world. It’s a subject often discussed or referred to here on this blog when a post concerns the ringing of birds. 

We know lots about bird migration, most of it gleaned through the ringing of birds, but there is still a great deal to learn. There are techniques developed in recent years which have the potential to add to our knowledge of how, when, where and why birds orientate and navigate. There are new and developing methods like data logging through radio tracking, radar observations or aural (listening). The physiological basis for bird migration has also received considerable attention, particularly the effects of seasonal increases and decreases in daylight and the seasonal rhythms that influence birds’ movements. 

But now a new study shows that small birds migrating from Scandinavia to Africa in the autumn occasionally fly as high as 4,000 metres (about two and a half miles) above sea level - probably adjusting their flight to take advantage of favourable winds and different wind layers.

The study concerns two species I see at migration time each year in Menorca and Greece, May and September respectively – the Great Reed Warbler and the Red-backed Shrike. 

Red-backed Shrike 

This is the first time that researchers have tracked how high small birds fly all the way from Sweden to Africa. Previous studies have successfully logged the flying height of larger migratory birds. 

The aim of the study was to investigate whether the measuring method works on small birds, which involved measuring acceleration, barometric pressure (air pressure) and temperature throughout the flight using a small data logger attached to the bird. 

A data logger was attached to two individuals of different species: Great Reed Warbler and Red-backed Shrike. Among other things, the results show how long it takes for each bird to fly to their destination. The measured barometric pressure showed that Great Reed Warbler occasionally flies at altitudes of up to 3,950 metres, while Red-backed Shrike flies at up to 3,650 metres. Both individuals flew the highest above ground across the Mediterranean Sea and the Sahara, but the shrike also reached high flight altitudes closer to its winter grounds in southern Africa. 

Great Reed Warbler 

Red-backed Shrike 

"We only followed two individuals and two species. The fact that both of them flew so high does surprise me. It's fascinating and it raises new questions about the physiology of birds. How do they cope with the air pressure, thin air and low temperatures at these heights?," says Sissel Sjöberg, biologist at Lund University and the Zoological Museum in Copenhagen. 

Both individuals flew the highest above ground across the Mediterranean Sea and the Sahara, but the shrike reached higher flight altitudes closer to its winter grounds in southern Africa. 

Sissel Sjöberg thinks it is likely that other small birds fly as high, maybe even higher. But there is no evidence of that yet. 

"In this study, we only worked with data collected during the autumn, when the small birds migrate to Africa. There are other studies that indicate that the birds fly even higher when they migrate back in the spring, but we cannot say for sure." 

Great Reed Warbler - photo credit Vitalii Khustochka 

There's one thing for sure. The next time I see those two species, I will think of them in a new light and try to imagine them heading to and from Africa two and a half miles above me. Up there - somewhere in the sky. 

Journal Reference: Barometer logging reveals new dimensions of individual songbird migration. Journal of Avian Biology, 2018.

Linking today to Eileen's Blogspot.