BTO Cymru

Croeso i blog BTO Cymru. Welcome to BTO Cymru's blog

Wednesday, 8 January 2020

Why count Herons? Pam bod angen cyfrif crëhyrod?



                                                                                                     Photo:   Liz Cutting

The BTO Heronries Census began in 1928 as a one-off investigation for the journal British Birds but has matured into an annual survey still ongoing more than 80 years later. Its Grey Heron data represent the longest-running monitoring data set for any breeding bird in the world.

Yn 1928, gwnaeth y BTO gyfrifiad o’r crëyr glas ar gyfer y cyfnodolyn British Birds. Ymchwiliad  unwaith ac am byth oedd hwn i fod, ond y mae wedi aeddfedu i fod yn arolwg blynyddol, sy'n dal i gael ei gynnal dros 80 mlynedd yn ddiweddarach. Eu set o ddata am y crëyr yw’r set monitro mwyaf cynhwysfawr ar gyfer unrhyw aderyn bridio yn y byd erbyn hyn.




The simple aim of the Heronries Census is to collect counts of 'apparently occupied nests' (aon) of herons, egrets, cormorants  and other colonial waterbirds from as many heronries as possible in the United Kingdom each year.

Nod syml Cyfrifiad y Crëyr Glas yw casglu cyfrifiad o’u 'nythod ymddangosiadol' (h.y. rhywle ble y mae’n edrych yn debygol bod nyth yno eleni). Yr adar dan sylw yw’r crëyr glas, crëyr bach, bilidowcar ac adar dŵr tiriogaethol eraill, a gobeithir cofnodi cynifer o grëyrfeydd â phosibl bob blwyddyn yn y Deyrnas Unedig.

Many heronries hold a dozen or more nesting pairs, even a hundred or more, and occupy traditional, well-known sites that are active for many decades, and some of the heronries in the census are known to date back to the nineteenth century. Smaller and shorter-lived heronries must also be included in the counts, however, to ensure that the data represent the whole population. Even single nests of any of the normally colonial heron or egret species are relevant to the Heronries Census, even if only occupied for one season.

Mewn llawer i grëyrfa, ceir dwsin neu fwy o barau yn nythu, ond weithiau ceir hyd at gant neu fwy. Ar y cyfan, y mae eu safleoedd nythu yn bur sefydlog - maent yn aros yn yr un llefydd am ddegawdau ac y maent felly yn llefydd eithaf hysbys. Mae rhai o'r crëyrfeydd yn y Cyfrifiad yn dyddio'n ôl i'r bedwaredd ganrif ar bymtheg. Fodd bynnag, mae yn rhaid cynnwys crëyrfeydd llai a rhai ‘dros dro’ yn y Cyfrifiad, er mwyn sicrhau bod y data'n cynrychioli'r boblogaeth gyfan. Dylid cynnwys hyd yn oed nythod sengl unrhyw un o deulu’r crëhyrod yn y Cyfrifiad - hyd yn oed os mai dim ond am un tymor y maent yno. Mae newidiadau yn nifer y nythod dros amser yn fesur clir o dueddiadau eu poblogaeth. Po fwyaf o grëyrfeydd y gellir eu cyfrif bob blwyddyn, y mwyaf sicr y gallwn fod o dueddiadau poblogaeth ar raddfa genedlaethol, rhanbarthol a lleol. 

Changes in the numbers of nests over time are a clear measure of population trends. The more heronries that can be counted each year, the more certain we can be of population trends at national, regional and local scales. The Welsh trend is similar to the UK trend, although the Welsh trend begins in 1934 due to insufficient coverage in the first few years, with the effects of severe cold weather on herons apparent.

Mae tueddiad Cymru yn debyg i duedd y DU (er bod data Cymru yn dechrau ym 1934 oherwydd diffyg sylw yn yr ychydig flynyddoedd cyntaf) ac y mae effeithiau tywydd oer difrifol ar y crëyr glas yn amlwg. Mae'r set ddata yma yng Nghymru yn adlewyrchu natur y wlad - gyda digon o ddata ar gyfer yr ardaloedd mwyaf poblog ond mae prinder data ar gyfer mannau eraill.

The dataset here in Wales reflects the nature of the country with good coverage in well inhabited parts of the country and no so in others.  If you feel you would like to take part in this very long running survey, it’s only a couple of visits to your local heronry every spring, and some data entry. If however you feel you would like to do more we are happy to oblige.


Os ydych yn teimlo yr hoffech gymryd rhan yn yr arolwg hwn, dim ond cwpl o ymweliadau â'ch crëyrfa leol fydd ei hangen a hynny yn y gwanwyn, ac wedyn ychydig o fewnbynnu data. Fodd bynnag, os ydych yn teimlo yr hoffech wneud mwy, byddwn yn ddiolchgar iawn.


We are also in the process of updating our heronries site list. We know that many of our sites which haven’t been visited for some time will have been abandoned by herons but a few of them will still be active or may have been reoccupied, so we are also looking for observers who are willing to explore one or more of these historical sites to see if you can find any signs of recent nesting activity in the area. Although many of these visits will be negative, these confirmed ‘zero counts’ are just as important to us as counts from active sites when it comes to ensuring our population estimates are accurate. Even if herons are no longer present, we are sure that many of the sites will hold other interesting wildlife.

Yr ydym hefyd yn y broses o ddiweddaru ein rhestr o safleoedd nythu y crëhyrod. Gwyddom bod y crëhyrod wedi hen ymadael rhai o'r safleoedd nad ymwelwyd â hwy ers tro, ond efallai y bydd yr adar wedi dychwelyd i rai ohonynt ac yr ydym felly yn awyddus i gael gwirfoddolwyr i archwilio un neu fwy o'r safleoedd hanesyddol hyn i edrych os oes unrhyw arwydd o weithgaredd nythu diweddar yn yr ardal. Er y bydd llawer o’r ymweliadau hyn yn negyddol, mae cadarnhau ‘cyfrif sero’ fel hyn yr un mor bwysig i ni â chyfrifiad fel arall er mwyn sicrhau bod ein hamcangyfrifon poblogaeth yn gywir. Hyd yn oed os nad yw crëyr glas yn bresennol mwyach, yr ydym yn siŵr y bydd llawer o fywyd gwyllt diddorol yn yr ardal.

For more information and local organiser contact details go to the BTO web pages About Heronries Census pages. 

I gael mwy o wybodaeth a manylion cyswllt y trefnydd lleol, ewch i dudalennau gwe BTO About Heronries Census

Monday, 18 November 2019

Welsh Ornithological Society / BTO / RSPB conference




Saturday 16th November saw the 30th Anniversary Conference of the Welsh Ornithological Society at the University of Aberystwyth. It was a huge success, with almost 150 delegates attending, including an encouraging number of talented young ornithologists.

Tony Cross was presented with the society’s Lifetime Achievement Award in recognition of his long term work on key Welsh species. His roll of honour is too long for this post but for those who don’t know Tony is renowned and respected for his expertise and knowledge gained from many long term ringing programmes. The go-to man for Red Kites, Barn Owls, Chough, Curlew, Dippers, Hawfinches, Pied Flycatchers, Kestrels, Ravens, terns, swans, Woodcock, and Nightjars across Wales.



 Jack Devlin of Cardiff University received the Student Award for his well-researched and highly topical work on Pheasants and their impact on invertebrate communities in upland Wales.


The presentations were worthy of such a special occasion, with Iolo Williams reflecting on the past 30 years of birds in Wales and gazing into his crystal ball for possible scenarios for the next 30 years – not all doom and gloom, but the threats to wildlife are all too evident and present.


Tim Birkhead presented outcomes from one of the country’s longest running studies – 47 years of Guillemots on Skomer – and did his best to convince us that Guillemots were far more lovable and interesting than Puffins!  I now know why a Guillemots egg is shaped as it is. Although it’s almost invidious to identify one single highlight from the conference, the mixture of poetry, passion and good science in Mary Colwell’s presentation on Saving Curlews will live long in the memory of all who were fortunate enough to hear and see this.

In the afternoon, an innovative feature was Question Time, chaired by Steffan Messenger, BBC Environment Correspondent, featuring a panel of Katie-Jo Luxton (Wales RSPB Director), Andy Clements (BTO Chief Executive) and Mark Isherwood (AM and active species champion for Curlew) and pertinent and topical questions from the audience. The final session of the day was presented by Steve Stansfield, Warden of Bardsey BO, enthralling us with highlights of the changing seasons on this magical island. Has anyone in the audience actually seen 365 Grasshopper Warblers, let alone all in one day!
The presentations, more photos and news from the day will be on the WOS website shortly. Next year’s conference will be held in the south west of Wales and it will be some job to keep the quality of the speakers up.

Many thanks to Bob Haycock for the photos

Wednesday, 11 September 2019

Welsh Ringing Course, September 6-9, 2019 A trainee’s view





                                      Members of the course trapped over 500 birds during the weekend



   It is 11pm on the first night of the course, and our group is already out on the wild and remote Gower coast, with far-reaching views to the lighthouse on Lundy, and the waterfront at Llanelli. We are getting a lesson in dazzling waders.

We take it in turns individually to go out with Tony Cross, one of the UK’s most experienced lampers, and a man rumoured to ring at least one bird every day of his life.

In a couple of hours we net 32 birds: Dunlin, Ringed Plover, Turnstone and Sanderling.
Given a surfeit of enthusiasm, we have some difficulty persuading Tony to stop. Only the prospect of an early start in the morning eventually forces us home, after a cracking start to the weekend.



                                              A young Grey Wagtail caught at Oxwich on the course


Next morning we start mist-netting on Oxwich Marsh, a mixed scrub and reed site which yields a good variety of warblers, finches and pipits.

Among the top species were 2 Grasshopper Warblers, 11 Stonechats, 3 House Martins and no less than 7 Tree Pipits. Later we catch some 50 Swallows and Wagtails at an evening roost.

One of the biggest revelations for me personally was the use of spring traps, baited with meal worms.
Martin Thomas rings a good proportion of all the Meadow Pipits ringed in Wales using this method, and he demonstrated just how effective they can be. Over 2 afternoons he caught 15 Rock Pipits in a small coastal cove, which was a new species for all of us trainees.

In poor weather, or for a C permit holder without a mist net endorsement, these traps provide an excellent alternative.

                                              A Rock Pipit caught with a spring trap

We were lucky with the weather, and caught a little over 500 birds in total, so the trainees got to process an average of around 50 birds each. One of our team managed 10 new species!  (see totals below).

That having been said, this course has consistently caught reasonable numbers of birds, even when the weather has not been so kind. Wader dazzling and spring traps provide flexibility if it is wet or windy – which in September is a greater risk.

Last but not least, course organiser Kelvin Jones sends out a brilliant after-care package, containing tips on ageing and moult, and a series of quizzes, certain to cause hours of debate over a pint.


If you are looking to choose a course, here’s why you should consider this one:

1.      The philosophy is about learning and having fun. It is distinctly non-competitive and friendly. So no one is going to shout at you for making a mistake. It feels genuinely inclusive, with equal numbers of male and female participants.

2.      There are only ten trainees on the course, divided into two groups of five, which means an excellent teacher/pupil ratio.

3.      You will be on the Gower Peninsular, a spectacular part of the country. The 2019 course attracted attendees from as far away as Norfolk, Liverpool and Yorkshire
.
4.      If the weather is bad, there are alternatives to mist netting.

5.      The ringing programme is brilliantly organised by Owain Gabb, with help from lots of Gower Ringing Group field assistants, who open the nets, do all the scribing etc. Martin Hughes from Northumberland and Justin Walker from the BTO were excellent tutors
.
6.      Accommodation is in bunk beds indoors. Mostly dormitories, but some smaller rooms are also available. Basic comfort, but great if you don’t fancy camping. Breakfast and dinner included, for a very reasonable cost
.
7.      The Gower Inn is 60 seconds walk from the accommodation. What’s not to like??

Brian Milligan, course participant


Species Name
Ringed
Recapt
Total
Blackbird
8
6
14
Blackcap
65
1
66
Blue Tit
32
33
65
Bullfinch
1
1
Cetti's Warbler
3
5
8
Chaffinch
3
3
Chiffchaff
29
1
30
Coal Tit
1
1
2
Dunlin
7
7
Dunnock
8
7
15
Garden Warbler
1
1
Goldcrest
6
6
Goldfinch
1
1
Grasshopper Warbler
2
2
Great Spotted Woodpecker
1
1
Great Tit
10
9
19
Greenfinch
23
23
Grey Wagtail
6
6
House Martin
3
3
Long-tailed Tit
7
5
12
Pied/White Wagtail
11
11
Reed Bunting
4
4
Reed Warbler
18
3
21
Ringed Plover
11
11
Robin
14
9
23
Rock Pipit
13
2
15
Sand Martin
1
1
Sanderling
1
1
Sedge Warbler
12
1
13
Song Thrush
1
1
Stonechat
11
11
Swallow
59
59
Tree Pipit
7
7
Turnstone
13
13
Whitethroat
6
3
9
Willow Warbler
9
9
Wren
10
8
18
Grand Total
417
95
512