Showing posts with label Birdfacts. Show all posts
Showing posts with label Birdfacts. Show all posts

13 September 2017

Record breakers of the bird world

Bird ringing has come a long way since it's inception in 1909. It was primarily set up to answer some basic questions, like where do our birds go and how long do they live. Since then, an amazing amount of information has been gathered that answers many more complex questions, like why a certain species population changes each year and where in Britain or Ireland are they declining. More information can be found on the BirdTrends and ringing surveys pages.

https://www.bto.org/volunteer-surveys/ringing/surveys/ras

 https://www.bto.org/volunteer-surveys/ringing/surveys/ces

At this time of year, all of the previous year's data have been loaded and checked and the Ringing and Nest Recording Team pull together some of this information to produce the Online Ringing & Nest Recording Report. The report includes annual totals for ringing and nest recording, as well as information on recoveries, but it also covers one basic question... how long can a bird live?

The longevity records for 2016 have now been updated and there are some interesting new records. Relatively new colonists like the Little Egret often feature. As they have only been ringed in any numbers in Britain and Ireland in the last fifteen years, we probably haven't yet established the normal maximum life expectancy; the record currently stands at 10 years and five months.

Little Egret chicks. Photo by Graham Giddens
Last year saw 17 records broken including three owl species; Barn Owl, Little Owl and Tawny Owl with ages reaching 15 years, 13 years and 23 years respectively. Some finches also did well with Twite, Lesser Redpoll reaching six years and Goldfinch reaching 10 years.

Lots of these record breakers were caught by a ringer, as opposed to being found dead or being identified by colour marks. Where ringers monitor the same populations annually, the potential for individuals to be caught again increases. This is exactly what happened with three of the record breakers, Little Ringed Plover, Peregrine and Nuthatch, which broke their own records after being re-encountered in 2016! 

The Puffin longevity record was broken again in 2016, and the oldest-known bird in Britain or Ireland is now a ripe old age of 37 years. The individual that broke the record, seen in the photo below, was ringed and re-encountered by the Shiants Auk Ringing Group, who ring in the Western Isles. The previous record holder was also a bird from the Shiants.

The oldest-known BTO-ringed Puffin, by Liz Scott.

We won't be analysing the 2017 records until next year but we already know that the current longevity record for Jackdaw has been broken. Originally ringed in April 1999 by Declan Manley, and subsequently re-caught in 2005, 2007, 2012 and now in 2017. A Goldfinch ringed in Nottinghamshire and found dead in Devon has also broken the 2016 longevity, adding another couple of months on to the current record.

Longevity records are the maximum a species has been recorded to live but most birds do not manage to reach this age. The average life expectancy and lots of other interesting facts can be found on our BirdFacts page.

21 April 2017

Little Owls in Lincolnshire

Anecdotal reports suggest that some species have started breeding early this year. In this post, Bob Sheppard provides an update on the Little Owls he monitors in Lincolnshire:

Little Owls readily take to nest boxes, particularly in old farm buildings. The box design I use is important as it mimics a hole in a tree. My father designed the box back in 1998.

A very big clutch of Little Owl eggs. Taken by Bob Sheppard/Alan Ball.

In the past nineteen years our Little Owls have increased as more boxes have been installed and we now have 80 pairs breeding. We monitor the adults for the Retrapping Adults for Survival scheme as well as submitting records to the Nest Record Scheme. In late April/early May, my colleague Alan Ball (who works with me to monitor all the boxes every year) and I catch all the adult females at the boxes (males are rarely caught in the boxes). The females are very site faithful and so we often retrap the same birds for several consecutive years. We then make a follow up visit to ring the chicks.

Little Owl struggling to sit on all those eggs. Taken by Bob Sheppard/Alan Ball.

This year we have found eggs during the first week of April which is very early indeed for Lincolnshire. Clutches of four are the average but we do find quite a few fives, including three already this season. Six egg clutches are not unknown and we once had a seven! The egg-laying season is unusually staggered this year; in several boxes we have heavy females yet to lay. Recoveries are rare (see online reports) but we meet lots of old friends as we open the boxes.

Ed - For more information on the details of Little Owl biology, see our BirdFacts page. Lincolnshire holds the record for the highest number of nest records of Little Owl (77) in 2016, with Norfolk following quite a way behind (14). For the 2015 results of any species click here.

19 January 2012

It's Loony that we only get one a year!

Birdfacts quote: "In Shetland Red-throated Divers were considered one of the best weather indicators, short cries (or flying inland) indicated fine weather, long, plaintive ones (or flying out to sea) wet weather." Although probably not a statistically significant weather predictor, the Red-throated Diver is an amazing bird.


Occupying shallow ponds and lochs in Scotland during the summer and heading out to sea in winter, this bird is tricky to see, let alone ring, unless you live on Shetland, Orkney or the Western Isles. In 2010 we ringed 91 birds and all apart from three were ringed as chicks from broods of one or two.

In 2010 we had one report of a Red-throated Diver, ringed in Sweden (red pin) on 31 July 1996 and found fresh dead on 6 February 2010 in North Wales (1326km). We have just heard that we have now had our annual quota of foreign ringed Red-throated Divers for 2011 in the form of a bird ringed in Finland (blue pin). This bird was ringed on 28 July 2008 and found dead on Stronsay, Orkney on 13 November 2011 (1753km).


View Red-throated Diver in a larger map

Thanks to Jill Pakenham for the photo.