24 July 2015

Found a ringed bird? You are not alone.

With around one million birds ringed every year it is not surprising that we get quite a few phone calls and lots of emails to the ringing team from non-ringers reporting a ringed bird. We get back to each one a few days later with a report on where and when the bird was ringed, and at the same time let the ringer know that one of 'their' birds has been found.

When you add this to all of the recaptures of ringed birds by our ringers through general ringing, especially structured ringing like Constant Effort Sites and Retrapping Adults for Survival, the value of these reports to conservation is huge. There are many aspects of a bird's life that can be investigated by BTO scientists and academics, particularly when results from other BTO surveys, such as the Nest Record Scheme and BBS, are included in the dataset.

Great example of part of a Dunnock nest record by Christopher Rowe

Most of the non-ringers that report ringed birds just get information on the bird they found and are unaware of the magnitude of records that we process. I have looked into the 40,394 reports that have been sent to us so far this summer (since 29 March 2015) from ringers and non-ringers.

Below is a chart showing the percentage of each species that were found by non-ringers and caught by ringers. Blue and Great Tit are of course the top two, followed by other garden birds. Starling is unusually high due to some great Starling colour ringing projects operating from Essex to Montrose. We have had singles of some unusual species so far this summer including Icterine Warbler, Capercaillie, Ruddy Duck and Great Bustard but these are few and far between.

Finding reports sent in to the BTO so far this summer from ringers and non-ringers. Click chart to enlarge.

The chart below is purely those reported by non-ringers. Considering the recent declines in House Sparrow and Starlings, the reports of them are quite high but this is due to the increased conservation effort and colour ringing projects occurring on these species. Fifteen percent for Black-headed Gull isn't surprising for us as a large percentage of the Recoveries Officers' work is processing colour ring sightings of these birds moving between countries and within our country. There is also a large number of people devoted to gulls and ring reading.

Finding reports from this summer from non-ringers only

Our valued BTO ringers not only ring large numbers of birds, to increase our understanding of our bird populations, but they also recapture large numbers of birds that are already ringed. This accounted for 81% of all the birds 'encountered' and reported since 29 March. These are reported to us using a dedicated computer program and thankfully need less processing than non-ringer reports. Out of the non-ringers reports 78% are colour ring sightings - see below for the top 10 circumstances of the report. Discerning the cause of death can be difficult and these records are represented by the red slice on the chart below.

The top 10 circumstances that led to us getting a report this summer.

13 July 2015

Another Hawfinch season over

With the short Hawfinch season over, it was time for Jerry Lewis to reflect on how it had gone this year.

After his best ever season last year, 2015 had been a "bit slow" with just 94 birds ringed, and 34 recaptured from previous years (but good quality data for the RAS). One bird however was particularly noteworthy and was Jerry's second record of an eight year old bird. The previous bird (see here) could not be individually identified so its age could have ranged from a couple of weeks under eight years, to a few days over. On 2nd June, RSPB researcher, Rob Hughes, was watching one of the feeding sites, and saw a male with a white colour ring (which was unusual as orange rings had been used for the previous two years).

Mystery Hawfinch by Rob Hughes

While doing some routine mist netting with Will Kirby and Andy Stanbury, they caught the bird on 3rd June, and Jerry caught him again on 18th. It turned out to be NW31557, first ringed on 27 April 2007 at the same feeding site. In the intervening years, he had been caught three times in April 2009 (at the same site), and once more on 26 May 2013 (at a feeding site some 15 km to the south). His original single colour ring was missing on this last recapture, and he was fitted with a new inscribed colour ring - white inscribed with ZH. There is no way of knowing where he has spent most of the intervening years, but he had obviously not been regularly visiting any of the feeding sites. The latest capture is probably (see below) a new UK longevity record at 8 years, 1 month, 22 days.

Hawfinch by Rob Hughes

08 July 2015

Nest with the best

Over 250 keen NRS participants have attended BTO nest recording courses since veteran recorder and volunteer tutor Tony Davis ran the pilot in 2008. This year, thanks to BTO Scotland and recorders Colin Davison and Gilian Dinsmore, the regular weekend courses in Norfolk and Surrey were joined by a brand new afternoon workshop at Scotland's Big Nature Festival.

Punchbowl pipits

Five weeks ago nine more keen recorders met Tony at the Devil's Punchbowl in Hindhead, Surrey, to spend a weekend increasing their nest finding knowledge. Saturday was spent learning to find warbler and finch nests in gorse at a nearby heath, and looking for Skylark nests at Butser Hill. Then on Sunday the group descended into the Punchbowl itself and soon found what appeared to be two Tree Pipit territories either side of the main path. The next hour was spent practicing watching nesting activity unobtrusively, which for wary Tree Pipits often means at least 50 metres back! One pair turned out to be feeding fledged chicks and an hour spent on the other territory proved inconclusive—at least for the target species. After standing in the same spot for 20 minutes, attendee Colin became aware of a Robin stealthily taking food into a patch of gorse immediately behind him. The bird was watched carefully for two more visits, the 'hotspot' was searched, and a nest found containing four young. Nest number 15 out of 25 found over the whole weekend—plenty for Tony to follow up!

Top: Colin Wilson searches for a Robin nest after watching an adult carrying food. Bottom: Trainee Teifion Thomas rings a brood of Robins from another nest, while ringer Colin Wilson supervises

Scotland's Big Nature Festival

The weekend before the Surrey course, Scotland's Big Nature Festival played host to its first ever nest recording workshop, thanks in part to a local volunteer who couldn't actually be there on the day. Keen for the workshop to include an outdoor demo where people could be shown nests and how recorders safely monitor them, BTO Scotland realised that one of the country's top nest recorders, Colin Davison, lived near the venue. When they contacting him about helping, Colin said that he was working that day but would try to find a few nests in advanceand then promptly located 12!

Top: veteran nest recorder Colin Davison pointing out the location of a Chiffchaff nest. Bottom: Ben Darvill takes people on a bird song tour as part of BTO Scotland's roster of events at the 2015 Big Nature Festival
The workshop was very well attended and began with talks from Mark Wilson (BTO Scotland) on why Scotland needs more nest recorders and another local recorder (and Reed Warbler expert) Gillian Dinsmore on her experiences getting started. Mark and Gillian then announced the outdoor demo and were delighted when 30 keen members of the public stepped forward. Folk were divided into groups and taken on carefully planned tours of Colin's nests, which included some in cover (Blackcap with eggs, Robin with chicks), some on the ground (Skylark and Meadow Pipit, both with eggs), and a Blue Tit nest in an unbelievably narrow crack on the wall of one of the observation hides. It was great to see so many people interested, especially given the pressing need for more recorders in Scotland, and needless to say plenty of NRS starter packs were given out. Both Colin and Gillian have pledged their support for future workshopshopefully Colin will be able to attend the next one!

Interested in going on a nest recording course? Please see here.

A huge thanks to volunteers Tony Davis, Colin Davison and Gillian Dinsmore for making this years' courses/workshops possible, and a huge thanks to BTO Scotland staff Ben Darvill and Mark Wilson, and BTO Thetford staff Mike Toms, Hazel Evans and Debbie Todd. And of course thank you to all the course and workshop attendees!

23 June 2015

A Knot eggstravaganza

Delaware Bay, on the east coast of America, is positioned on the West Atlantic Flyway and is the final staging area for many thousands of waders on their migration from their South American wintering grounds to their Arctic breeding grounds. In spring, the Bay is also home to Horseshoe Crabs. These prehistoric-looking creatures spawn on the beaches in their thousands and their tiny eggs are full of protein – just what hungry waders need to replenish their body fat and to provide them with enough energy to complete their journey north.

The Horseshoe Crab eggs that the birds rely on. Photo by Ruth Walker

Unfortunately, for a number of complex reasons, the shorebird populations have diminished in recent years. As a result, in the mid-1990’s, Wash Wader Ringing Group members helped American scientists to establish the Delaware Shorebird Project. The project aims to research and monitor the health of the wader populations on the Delaware side of the Bay in order to better understand the connection between the birds, Delaware Bay and the Horseshoe Crabs. A sister project runs concurrently on the New Jersey side of the Bay. The birds use both sides of the Bay to feed, often swapping shores to avoid inclement weather. The data gathered are helping to identify and protect the resources that are so critical to the success of the wader migration. In part due to the work of the project, the key target species for the project, Red Knot, has recently been officially recognised as ‘threatened’ by the US Fish & Wildlife Service.

Red Knot. Photo by Ruth Walker

Location of Delaware Bay on the Red Knot's spring migration route

A number of BTO ringers, including BTO staff, still travel out to Delaware each May using their holiday time to volunteer alongside other researchers from around the world on this important project. The study aims to catch and fit individually coded colour flags to 350 individuals of each target species each year: Red Knot, Ruddy Turnstone, Sanderling (all of which are colour flagged) and Semi-palmated Sandpiper (though these are not flagged on the Delaware side of the Bay). Samples of Dunlin and Short-billed Dowitcher are also ringed and measured if caught. During their time in the Bay, birds can double their body weight and therefore catching birds throughout the season is vital to ascertain their fitness levels. In order to survive their migration, it is thought that Red Knot need to weigh at least 180g when they depart (having arrived a couple of weeks earlier weighing 110-120g).

The very similar looking Semi-palmated Sandpiper (left) and Sanderling (right). Photo by Ruth Walker

We aim to ensure that approximately 10% of the Red Knot population passing through the Bay are flagged, along with smaller percentages of Ruddy Turnstone, Sanderling and Semi-palmated Sandpipers. Because waders are global travellers, flagging projects are undertaken in a number of different countries. The flag colour indicates the country the bird was flagged in, so birds caught in Delaware have a green flag, but we also see birds with red (Chile), orange (Argentina), blue (Brazil) and white (Arctic) flags . We attempt to catch approximately every three days so that we have weight samples throughout the stopover period, with the rest of the time spent counting the numbers of birds using each of the beaches each day, re-sighting the colour-flagged birds as well as the seemingly endless task of entering and checking all of the data. Re-sighting colour-flagged birds not only gives information on arrival and leaving dates and movements of individual birds within the Bay, but also information on survival and the total number of birds using the Bay.

An American-ringed Ruddy Turnstone foraging. Photo by Ruth Walker 

This year, 362 Red Knot were caught, along with 284 Ruddy Turnstone, 75 Sanderling, 407 Semi-palmated Sandpipers, 472 Dunlin and 78 Short-billed Dowitchers. It was very pleasing to see that of the Red Knot ringed during the final catch of the season, 74% weighed more than 180g, 23% were over 200g with the heaviest bird weighing in at a whopping 228.6g! Thankfully, only 4% weighed less than 150g and would need to remain for longer in the Bay.

As the birds departed the Bay, so did the BTO staff and other volunteers. We look forward to catching up with the birds again next year! 

16 June 2015

Buzzard nest with a difference

We were contacted recently by Sam Bayley with the following fascinating story:

Early June marks the time when I check out a few of the many raptor nests that are present in my local area. After discovering three active Buzzard nests and a Kestrel nest I got a small team together including the invaluable help of tree climbers Max Varney and Sam Baker. The first two Buzzard nests and the Kestrel nest were very straightforward with broods of one and two Buzzards and a good brood of five Kestrels, but the third Buzzard nest at South Holmwood was something entirely different!

I had ringed this nest in 2014 when it contained three chicks and it was very typical with lots of evidence of rabbit unsurprisingly being the main food supply. It was very evident even from the base of the tree that this year was different, with a scattering of feathers on the ground below the nest. On reaching the nest Max and Sam found two Buzzard chicks and an unhatched egg surrounded by the remains of various species of bird. Buzzards will take birds, but only occasionally as they aren’t particularly adept at catching them and when they do it is usually limited to chicks or newly fledged birds. The species identifiable were Stock Dove (adult), Jackdaw (adult and nestling), Jay (newly fledged), Moorhen (adult), Great-spotted Woodpecker (adult) and a single Rabbit bone! It looked more like the contents of a Goshawk nest rather than a Buzzard’s, but obviously this pair had become incredibly proficient at catching these birds.

The two Buzzard chicks. Photo by Max Varney

If that wasn’t unusual enough, Max and Sam could hear another bird calling from the nest and eventually realised that it was a Jackdaw chick which was in its own nest within the structure of the Buzzard nest! The adult Jackdaws had created a tunnel into the side of the nest with a chamber at the end, less than 30cm below the cup of the nest! The Jackdaw chick was much younger than its Buzzard counterparts, so I can only assume that the Jackdaws started nesting after the Buzzards were already in residence. 

The entrance to the Jackdaw nest. The two Buzzard chicks
are just visible in the top of the nest. Photo by Max Varney

The Jackdaw chick. Photo by Sam Bayley

Only an end of nesting visit will tell whether they all survive!