Náttúrufræðingurinn - 1999, Page 11

■ ÞAKKIR
Eftirfarandi gáfu upplýsingar um ábúð
hrafnsóðala og kunnum við þeim bestu
þakkir fyrir: Adam Jónsson, Aðalsteinn Þór-
ólfsson, Atli Vigfússon, Arni L. Kristbjörns-
son, Björn Benediktsson, Egill Freysteins-
son, Einar O. Björnsson, Einar Þorleifsson,
Finnur L. Jóhannsson, Friðbjörn Jónatans-
son, Gaukur Hjartarson, Guðmundur Bergs-
son, Guðmundur Héðinsson, Guðmundur
Jónsson, Guðmundur S. Jónsson, Gunnar R.
Pétursson, Gunnlaugur Þráinsson, Hall-
grímur Hallsson, Haraldur Sigurðsson,
Haukur Hreggviðsson, Hermann Bárðarson,
Héðinn Ólafsson, Hjörleifur Sigurðarson, Ib
K. Petersen, Indriði Ketilsson, Ingi Yngva-
son, Ingimundur Pálsson, ívar Stefánsson,
Jóhann Ó. Hilmarsson, Jónas Bjarnason,
Karl S. Björnsson, Magnús Þorsteinsson,
Ólafur Einarsson, Ólafur Jónsson, Pétur
Þorsteinsson, Sigurður Haraldsson,
Sigurður Yngvason, Sigurgeir Pétursson,
Sverrir Thorstensen, Torfi Aðalsteinsson
og Þórhallur Ásgrímsson. Veiðistjóra-
embættinu þökkum við fyrir afnot af gögn-
um um hrafnaveiði í Þingeyjarsýslum 1986-
1991 og veiðiskýrslum 1995-1997. Ingi
Yngvason veitti okkur upplýsingar um
hrafnaveiði sína árin 1981-1998 og kunnum
við honum bestu þakkir fyrir þær.
Guðmundur A. Guðmundsson, Kristinn H.
Skarphéðinsson og Ævar Petersen lásu yfir
handrit og færðu margt til betri vegar.
■ HEIMILDIR
Cade, Tom. J., Pertti Koskimies & Ólafur K.
Nielsen 1998. Falco rusticolus Gyrfalcon.
BWP Update 2. 1-25.
Kristinn H. Skarphéðinsson, Ólafur K. Nielsen,
Skarphéðinn Þórisson & Ib K. Petersen 1992.
Varpútbreiðsla og fjöldi hrafna á íslandi. Bliki
11. 1-26.
Kristinn H. Skarphéðinsson, Ólafur K. Nielsen,
Skarphéðinn Þórisson, Sverrir Thorstensen &
Stanley A. Temple 1990. Breeding biology,
movements, and persecution of Ravens in Ice-
land. Acta Naturalia Islandica 33. 45 bls.
■ SUMMARY
The status of the Raven TOPULATIN IN
ÞlNGEYJARSÝSLUR, NoRTH-EAST ICELAND
The Raven Corvus corax is a common and a
widespread bird in Iceland, breeding in lowland
areas and up to 500-600 m above sea level in the
highlands. In the mid 1980s thc population num-
bered 13,000 birds in aulumn, including 2,000
breeding pairs, 4,000 non-breeding birds, and
5,000 young (Kristinn H. Skarphéðinsson et al.
1992). The Raven has been regarded as a pest
bird in Iceland and always been persecuted. Sys-
tematic registration of total number killed was
started in 1995, since then 6,000-7,000 Ravens
have been killed each year (Wildlife Management
Institute, in litt.) (Fig. 1). Given a fairly accurate
population estimate in 1985, the Raven popula-
tion is probably over-harvested and should be
declining.
The purpose of this paper is to report on the
results of a population monitoring program for
Ravens in north-east Iceland 1981-1998, and
analyse the available information of Raven hunt-
ing in this same area. The study area is within the
counties of Suður- and Norður-Þingeyjarsýslur,
covering 5,327 knr (Fig. 2). In this area, a total
of 141 traditional Raven-nesting temtories are
known. Each year, in May through July, parts of
the Raven territories were visited and checked
for occupancy. The territories were classified
into four groups:
Breeding pair. At least one egg laid, some of
these pairs later failed.
Non-breeding pair. A pair observed or a new
nest found with no eggs.
Unknown occupant. No sign of nest-building,
but single bird and/or signs of Raven occupancy,
like droppings, feathers or pellets.
Unoccupied territory. No sign of Raven occu-
pancy at any of the known nest sites in the ter-
ritory.
The data for occupancy rate were used to ex-
trapolate the total size of the breeding popula-
tion in the study area each year. The sample was
not random; in most years it was large, or on
average 61% (range 21-89%) of the known tradi-
tional territories. Total number of young fledged
in study area was calculated using the rnean
number of young fledged per occupied territory
multiplied with the number of occupied territo-
ries. The first parameter, young fledged per oc-
cupied territory, was only measured in 1981-
1985 (Kristinn H. Skarphéðinsson et al. 1990);
the mean ftgure for this period, 2.1 young per
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