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Ringing & Migration
Journal of the BTO Ringing Scheme |
Ringing & Migration Volume 21 Part
1
Abstracts
[ For abstracts from Ringing Group
Reports click here ]
Autumn movements of Italian Sparrows Passer
italiae in central Italy
MARCO GUSTIN1* and ALBERTO
SORACE2;
¹LIPU, Lega Italiana Protezione Uccelli, Settore Conservazione,
via Trento 49, 43100 Parma, Italy
²SROPU, Oasi WWF-Bosco di Palo, Via di Palo laziale 2, 00055 - Ladispoli
(Roma), Italy and Laboratorio di Igiene Ambientale, Istituto Superiore
di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
In October 1998, we studied movements of Italian Sparrows Passer italiae
on the Italian Adriatic coast, through ringing and observations of the movements
of flocks. Both the absence of recaptures of the 247 Italian Sparrows that
were captured and the mean increase in fat during the study period suggest
that these Sparrows were moving through the study area. Two factors suggest
that the observed movements constituted an invasion rather than a regular
migration. First, the peak of captures was in the early afternoon and not
early in the morning, and second, all flocks were observed flying northward
and not southward which is the typical direction of most Paleartic birds
during post-breeding migration. An analysis of data from the Italian Ringing
Scheme showed that movements of Italian Sparrows ringed on the Adriatic
coast were the longest compared to other areas of origin. Movements of Italian
Sparrows are likely to be more common and extended than previously thought
and may promote the genetic flow both between conspecific populations and
between other Sparrow species (Italian, Spanish and House Sparrows) in Italy.
Redwing Turdus iliacus migration and
wintering areas as shown by recoveries of birds ringed in the breeding
season in Fennoscandia, Poland, the Baltic Republics, Russia, Siberia
and Iceland
R. D. P. MILWRIGHT
17 Forehill, Ely, Cambridgeshire CB7 4AA, UK
Recovery data from nominate Redwings Turdus iliacus ringed in four breeding
zones in Europe and Asia are analysed in 10 wintering watershed areas in
Europe, North Africa and Asia. Icelandic Redwing data are analysed separately.
Nominate Redwing data are heavily biased, with almost 60% originating in
Finland (4% of the world breeding range), but less than 1% from Siberia
(60% of the breeding range). Large numbers of autumn passage migrants visit
"Schelde" (Belgium/northeast France), and "Po" (North
Italy), but few winter in these areas. 78% of recoveries are in "West
France", "South France/West Italy" or "Iberia".
Hunting and habitat adjusted recovery rates indicate that "Gironde"
(southwest France) holds the heaviest concentrations of the nominate race.
Adult birds are more likely to winter in the more distant areas, Iberia
and northwest Africa, Cyprus, the Levant and Transcaucasus. Few ringed nominate
Redwings are recovered in Britain or Ireland but adjusted recovery rates
suggest these are moderately important wintering areas, where juveniles
are more likely to be in England or Wales and adults in Scotland or Ireland.
Icelandic Redwings winter almost entirely in Scotland, Ireland, western
France and northwest Iberia. Adjusted recovery rates indicate that Ireland
is much the most important wintering area for this race. Adults and birds
from eastern Iceland are more likely to be recovered in Scotland and Ireland,
while first winter birds and those from western Iceland are more likely
to be found in France and Iberia. The origin of the large waves of autumn
migrants seen in eastern Britain and eastern Spain remains obscure. More
ringing is needed to establish the migration and wintering areas of the
large Siberian populations.
Sexual size dimorphism in the critically endangered
Seychelles Scops Owl Otus insularis
D. CURRIE1, A. C. MATEMAN2,
C. M. LESSELLS2 and R. FANCHETTE2
1BirdLife Seychelles, PO Box 1310, Aarti Chambers,
Mont Fleuri, Victoria, Mahé, Republic of Seychelles
2Netherlands Institute of Ecology (NIOO-KNAW), Boterhoeksestraat
48, PO Box 40, 6666 ZG Heteren, The Netherlands.
The Seychelles Scops Owl Otus insularis is a critically endangered species
restricted to the forests of Mahé in the Republic of Seychelles,
Western Indian Ocean. This study presents the first biometric data collected
from live individuals and investigates the occurence of sexual size dimorphism.
Thirty-one birds were measured, and 30 of these were sexed by molecular
analysis of their DNA: 6 females and 24 males. Females were generally
heavier and larger than males. There was some variation in plumage colouration,
which was unrelated to sex, but no evidence of distinct colour morphs
as has been documented in other Western Indian Ocean Otus species.
Breeding origins of Redshank Tringa totanus
wintering at two neighbouring sites on the Severn Estuary: evidence for
partial racial segregation
NIALL H.K. BURTON1*, STEVE G.
DODD2, NIGEL A. CLARK1 and PETER N. FERNS3
1BTO, The Nunnery, Thetford, Norfolk IP24 2PU
2Wittanacre, Bringsty Common, Worcester WR6 5UJ
3PABIO, Cardiff University, PO Box 915, Cardiff CF10 3TL
The breeding origins and racial composition of Redshank Tringa totanus wintering
in the Cardiff area of the Severn Estuary were investigated using information
from ring-recoveries and biometric data. In total, between 1991 and 2000,
we received 56 reports from the breeding season of Redshank ringed at Cardiff.
These involved 36 different individuals, 31 reported from Britain and five
from Iceland. There was a slight bias in records within Britain towards
the north and west of the country. The proportion of adult Redshank of the
Icelandic race T t robusta present during the non-breeding seasons varied
according to the month of capture and, importantly, between two neighbouring
sites within the study area: Cardiff Bay and Rhymney. The latter site held
a higher proportion of Icelandic birds throughout the winter. Percentages
of Icelandic birds were lowest in October and November (2% and 27% at Cardiff
Bay and Rhymney respectively) and highest in February and March (27% and
61% at the two sites respectively). The proportions of British Redshank
T t brittanica in the populations at Cardiff were higher than in studies
in eastern Scotland, Teesmouth, The Wash, Merseyside and north Wales but
less than in north Kent. The apparent partial segregation of Icelandic and
British Redshank between Cardiff Bay and Rhymney may have been related to
differences in the availability of prey species at the two sites and/or
a result of differences in the competitive ability of the two races. The
segregation of Redshank between the two sites could potentially have increased
the impact of the impoundment of Cardiff Bay in 1999 upon British-born birds,
though lessened the impact for Icelandic-born birds. The potential for similar
segregation occurring elsewhere in other species of migratory birds needs
to be considered in determining the impact of any similar environmental
change.
Bird ringing in Britain and Ireland in 2000
JACQUIE A. CLARK, DAWN E. BALMER, JEREMY
R. BLACKBURN, LINDA J. MILNE, ROBERT A. ROBINSON, CHRIS V. WERNHAM, SUE
Y. ADAMS and BRIDGET M. GRIFFIN
BTO, The Nunnery, Thetford, Norfolk IP24 2PU, UK
This is the 64th annual report of the British Trust for Ornithology's
Ringing Scheme presenting work carried out and data received in 2000.
Ringing birds is an important tool for conservation and research, providing
information on survival, productivity and movements of birds. Much progress
has been made in developing Integrated Population Monitoring (IPM) models
to identify key aspects of a species' biology. Studies on Marsh and Willow
Tits and on Bullfinches focussed on developing models for these species,
which are of particular conservation concern. A further study described
some advances in statistical theory that can be used in IPM models. A
study of Redshank movements showed differences before and after closure
of a tidal barrage in Cardiff Bay in south Wales. Data collected by the
Constant Effort Sites (CES) Scheme showed mixed fortunes for breeding
birds. Adult numbers increased significantly for four species (Long-tailed
Tit, Sedge Warbler, Reed Warbler and Whitethroat) and four species showed
significant declines (Linnet, Garden Warbler, Blackcap and Willow Warbler).
Similarly, productivity increased significantly for three species (Blue
Tit, Blackcap and Willow Warbler) and decreased significantly for three
species (Reed Warbler, Chaffinch and Bullfinch). Initial work on a project
to develop standard CES methods across Europe is described. 101 datasets
for 43 species were submitted for the Retrapping Adults for Survival (RAS)
Project. The number of birds ringed in 2000 (734,235) was 8% lower than
the five-year mean 1995-1999. The recovery total (10,912) was 6% below
the mean of the previous five years (1995-1999). Recoveries of 156 BTO-ringed
birds and 81 birds ringed abroad are presented in the report, including
a number of significant movements of an unusual nature. Particularly noteworthy
are the first report abroad of a BTO-ringed Shorelark, the first BTO-ringed
Whinchat to be recovered on the wintering grounds and a Great Tit that
was ringed at Rybachiy in Russia in September 1999 and recaught in Cleveland
in February the following year.
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