Bird ringing at Blashford

Brenda has been ringing birds at Blashford for many years, and it has been a pleasure to observe some of her winter ringing sessions. The practise of bird ringing generates information on the survival, productivity and movement of birds, and is an important method to help us understand locally and nationally (and globally!) how and why populations are changing.

All bird ringing is conducted following BTO (British Trust for Ornithology) protocols by trained and licenced ringers, with assistance from supervised trainees. If you would like to learn more about this head to https://www.bto.org/our-science/projects/ringing.

Long tailed tit (Aegithalos caudatus)

A morning ringing… it’s an early start!
Birds are most active in the morning (not the sort of just before lunch lazy morning, the real ‘sun just got up and is only just peeking over the trees’ type of early!), so the mist nets are set-up to make the most of this, and as a general trend more birds are caught early, with the numbers tapering down until the nets are closed around lunchtime.

Close up of a mist net. Mist net including poles and guy ropes.

Mist nets are an invaluable piece of equipment for ornithologists, providing a safe method to catch birds for research. A mist net is made of very fine nylon netting and is almost invisible, hence the term ‘mist’. Each net has 5 evenly spaced thicker horizontal strings called trammels, which are secured to vertical poles at each end of the net to ensure even tension. Between each trammel is fine netting that arcs down into a sort of pouch. They fly into the net and fall into a pouch and await careful extraction. This is the part I find fascinating. On each net check (regular intervals throughout the session) Brenda determines which side of the net the bird flew into, so that she can extract it successfully. She uses a variety of holds to ensure the bird stays still and can be untangled from the net without harm. Once extracted they are placed into a small drawstring bag for safekeeping and taken back to the area which has been set up for processing.

Birds waiting to be processed. Table laid out with ringing equipment.

Biometric data is taken for each bird (e.g. wing length, weight) and age/sex determined (depending on time of year) by identifiable features related to moult, feather colouration and feather shapes, or if during certain times of year the presence of e brood patch or cloacal protuberance (CP). If the bird is a re-capture then it will already have a ring, but if it’s a new bird then a small metal ring is fitted around the right leg which has a unique identifiable number. The rings are made of wide, flat metal, which is pressed around the leg, ensuring the join is smooth and the edges are flush. Once the ringer is confident the ring can move up and down the leg with absolutely no impact on the bird’s movement, it is then released. Brenda has a fantastic way of teaching and is exceptionally calm and patient and has one bespoke piece of kit that she made herself, a knitted bird! This bird can be used to practise specific handling techniques, be fitted with bird rings etc, so that when a trainee comes to handle a live bird they are more confident in their abilities.

These unique ring numbers are vital, as the data on re-capture can tell us how old the bird is, where it may have flown from (therefore its range), helping to inform bird conservation efforts. This morning we caught around 25 birds, and (bearing in mind I class myself as ‘not really a birder’) being able to see so many birds up close and learn about their markings has really helped me in my quest to be better at bird ID!

Lesser redpoll (Acanthis cabaret)

A Siberian Visitor

at Blashford Lakes a number of bird ringing projects are carried out by specially trained volunteers under the auspices of the British Trust for Ornithology (BTO). They have been overseeing bird ringing for over 100 years now and almost all that we know about the migration, longevity and survival of our birds has been found out using the results. These are all vital to understanding how we can look after the birds we have got and try to restore ones we are losing or have lost.

At the simplest an individually marked metal ring is attached to the leg of a caught bird, it is examined to establish species, age, sex and condition and then released. Most of these birds are never reported again, but with many thousands caught the percentage found was still enough to establish something of the remarkable journeys they undertake. We have probably all heard that our summering Swallow spend the winter in southern Africa, but who would have guessed that the Blackcap that winters in your garden is not the one that was there in the summer, they are down by the Mediterranean, instead it is perhaps from SE Germany.

Today it is possible to use additional techniques such as colour-rings, radio and satellite tags, but these are expensive especially for smaller birds as they need to be very light indeed. Some species are rare and hide very well, so it is difficult to catch them in the first place and if you do they are very unlikely to ever be seen again and small sample sizes mean you are always unsure how typical the data collected will be. To gain a fuller picture of their lives techniques such as stable isotope analysis and DNA sampling can assist, if you are interested do a search, there is a lot of fascinating information out there..

Despite all these high tech and sometimes very costly techniques coming into the picture much of what we are learning is still coming form the traditional ringing, largely thanks to the shear size of the samples it can achieve. The other important role of traditional ringing is to train new recruits, it takes typically a year or two to complete basic training and many more to become expert or specialise in particular techniques or species.

At Blashford Lakes we have a colour-ringing project for Black-headed Gulls, a nestbox project and a Constant Effort Site (CES) as well as some winter ringing with training opportunities. Recently one of the regular sessions turned up a rarer than usual visitor, a Siberian Chiffchaff. A lot of Common Chiffchaff pass through the UK in the autumn, some stay the winter, but many more head on down to the Mediterranean. Chiffchaff breed right across Europe and into Asia, although all the same species, the birds get paler and greyer the further east you go and these birds also call differently, and it was one of these eastern birds that turned up. The pictures below show the difference in appearance between a “typical” Chiffchaff and the Siberian visitor.

Common Chiffchaff (left), Siberian (right)
Siberian Chiffchaff (left), Common (right)
Common Chiffchaff
Siberian Chiffchaff

This autumn seems to have been a good one for reports of these Siberian Chiffchaffs, maybe just a chance increase in sightings or perhaps indications of a change in migration pattern as seems to be happening with a number of other Siberian nesting species. Only time will tell and who knows maybe this bird will be reported again and add to our understanding of how migration is changing, or not.