As always seems to be the case by this stage of the winter, I am running well behind with feedback, currently some 3 - 4 weeks, for which apologies to those of you who are waiting. However, please appreciate that there have already been about 6,000 records winging their way to me so far.............!!!!!!!
The position looks as if we are well ahead this winter, but this is somewhat misleading, particularly in the Dublin area, as the intensive ring-reading there by Matt Silk of University of Exeter, as part of his PhD project, had yet to be entered by this time last year. However, I don't think anyone will mind my singling out Christer Persson, who has been out doing his own intensive work as usual this winter across County Dublin, which is mitigating to some extent, our loss of Matt on the ground.
Beyond that, one can see it has been a good winter of ring-reading as birds passed through Strangford Lough, and the overall spread of reporting remains good. And forgive me for saying a special "hi" to all you guys in Normandy - fantastic effort!! Give yourselves a good pat on the back!!
IRISH
BRENT GOOSE RESEARCH GROUP RING RESIGHTINGS
2014 / 2015
DATE :- 20.12.14
THIS REPORT INCLUDES ALL
RESIGHTINGS THIS SEASON (AFTER 01 JULY 2014), WHICH HAVE BEEN SUBMITTED THROUGH
THIS GROUP, OF LIGHT-BELLIED BRENT GEESE WITH COLOURED RINGS. THE FIGURES IN
BRACKETS SHOW THE POSITION AT THE SAME DATE LAST WINTER.
|
AYRSHIRE
DONEGAL
DOWN
GWYNNED
ISLE OF MAN
KERRY
L’DERRY
LOUTH
MAYO
MEATH
MERSEYSIDE
WEXFORD
|
- EAST
-
-
-
-
-
-
-
-
- RIVER TAMAR
- BRAADE STRAND
-
-
- CARLINGFORD LOUGH
-
-
- OUTER ARDS
- STRANGFORD LOUGH
-
-
-
- MALAHIDE ESTUARY
- ROGERSTOWN ESTUARY
- SKERRIES
-
-
-
-
-
-
-
-
-
- ALFTANES
-
- SELTJARNARNES
-
-
-
-
- LOUGH FOYLE
- CARLINGFORD LOUGH
-
- PORT (CRUISETOWN) BEACH
-
-
- THE MULLET
-
-
-
-
-
- SKYE
-
-
-
-
-
-
- NORTH SLOBS
|
3 (-)
11 (19)
- (1)
- (1)
- (2)
31 (-)
2 (-)
2 (-)
1 (1)
1 (-)
1 (-)
4 (1)
3 (-)
5 (1)
83 (125)
1 (1)
- (1)
3282 (1322)
113 (52)
1035 (290)
2 (-)
35 (34)
44 (49)
- (1)
127 (47)
- (3)
1 (-)
1 (3)
- (1)
- (1)
9 (1)
- (1)
- (1)
- (24)
- (1)
- (2)
- (1)
73 (32)
3 (-)
126 (22)
68 (47)
5 (7)
31 (-)
1 (-)
1 (-)
6 (-)
3 (1)
2 (5)
3 (2)
2 (-)
1 (-)
15 (-)
6 (-)
- (1)
33 (20)
14 (14)
16 (13)
2 (-)
3 (-)
7 (-)
|
|
3 (-)
5 (6)
- (1)
- (1)
- (2)
22 (-)
2 (-)
2 (-)
1 (1)
1 (-)
1 (-)
2 (1)
3 (-)
4 (1)
40 (68)
1 (1)
- (1)
1029 (678)
67 (39)
379 (169)
2 (-)
28 (15)
35 (29)
- (1)
17 (13)
- (3)
1 (-)
1 (3)
- (1)
- (1)
7 (1)
- (1)
- (1)
- (24)
- (1)
- (2)
- (1)
36 (20)
3 (-)
73 (22)
40 (40)
5 (6)
24 (-)
1 (-)
1 (-)
6 (-)
3 (1)
2 (2)
2 (2)
2 (-)
1 (-)
8 (-)
6 (-)
- (1)
22 (12)
12 (8)
8 (13)
2 (-)
3 (-)
7 (-)
|
I have been poking statistically at my own sightings material from Dublin for a couple of months; it made me terrified. This material is so full of biases that i initially sat with the feeling: it cannot be used for any sensible or constructive analysis at all. It is a conglomerate of unknown or uncontrolled biases. Everything out there: flickering air, high grass, creates biases, everything i do: clinging to the North Bull or walking deep inland to exploit unknown possibilities, checking newly ringed birds or checking new arrivals or checking old acquaintancies, creates biases. AND I HAVEN'T RECORDED THESE THINGS THE WAY I SHOULD HAVE DONE, i have no data on grass depth, flickering air, distances covered by myself, wind force, tides, etcetera, etcetera. I don't think we should burden the people already buckling under the strain of the project as it is, but how about a compulsory sheet for each excursion, to be filled in and stored in a cloud for future use? Can it be arranged? Future generations might bless us if we do it.
ReplyDeletePeople ask me: How do you do it? I use a telescope with 82 mm aperture, an eyepiece permanently taped to 60x magnification. For several years i had inferior tripods, and my good optics shivered in any moderate wind. Today i have a Manfrotto tripod, it's heavy as a sledgehammer, adequate. I have studied Graham's carriage: he stands like a coal-sack, point of gravity low, no movement at all, i cannot do that, so i hang on the tripod, put an arm over the telescope to steady it in any wind. I also hold my eye 5 mms out from the eyepiece, i have learned that from others, it works. And i am dressed in three layers, with a heat-reflecting jacket; i can stand still for two hours before i'm frozen to the bone.
ReplyDeleteYesterday i finally got a flock of 500 at the Red Arches, the first time for me this season. Gale force winds, cold like hell, and i feared that the flock would be flushed. So i established eye contact with people approaching, tried to make them see my predicament. It worked, for one hour, and i raised my hand and waved to each one that turned around. A good sighting session begins like that.
Then i started. The grass was too deep, but there was a small pool (mainly clay), where birds started drinking, or sifting mud; when they did that i managed to read, in all some thirty birds. But i soon discovered that it was the same birds that drank again and again. Some juveniles drank five times in an hour, some ringed adults three and four times. BUT THE MAJORITY DIDN'T DRINK AT ALL. Two RB birds never approached the pool, not a WB bird, not a WW bird.
So: we work and work and work in order to avoid bias, for example with the underlying intent "to read it all". In doing so we create new bias. One could say that statistics is there to handle it, but statistics is a blunt tool without informed "pointers". Yesterday i got my first batch of sightings from Red Arches, some gold nuggets in my strainer, but 75 % of the birds wouldn't play ball with me. I know what i did: create bias.
And how do i analyse? I create a parameter "months elapsed to e.g. the first ten sightings" for each bird. Try to restrict the analysis to a uniform environment; Iceland sightings distort the pattern, but they can be analysed on a dayscale. Then, if i don't want to calculate, i can plot the progress of each bird and detect if it's becoming less "readable". For BB birds, and for some RR birds, with lower sighting probabilities, one can use e.g. "months elapsed to the first five sightings". This illustrates one problem of the project; we are not studying an overall "light-bellied" brent, but blue brent and red brent and white brent and...
ReplyDeleteStability of course increases the radius of action; with his Questar Graham reads from farther away than anyone i have met, up to the optical limit of his instrument. But i have doubled my radius of action after i understood the importance of stability, and i brought my insights back to Sweden, where i have achieved a breakthrough in the number of whimbrel sightings the last two seasons, just by being able to stand still.
ReplyDelete