Fróðskaparrit - 01.01.1999, Blaðsíða 155

159
Notes on Two Migrant Moths from the
Faroe Islands, Agrotis segetum (L.) and
Noctua orbona (Hfn) (Lepidoptera,
Noctuidae)
Fráboðan um tveir ferðanáttfirvaldar, Agrostis segetum (L.) og Noctua
orbona (Hfn) (Lepidoptera. Noctuidae)
by Svend Kaaber1 and Solgerd Andreassen2
1. Digtervænget 2, DK-8000 Aarhus C. Denmark.
2. FO-460 Norðskáli, Føroyar.
Úrtak
Hin 21. juni 1996 varð eitt Agrostis segetum (L.) kalldýr
fingið á Oyrarbakka, og hin 7. juli 1997 varð eitt Noctua
orbona (Hfn.) kvenndýr fingið í Nesvík. Hesi bæði sløg-
ini av náttfirvaldi vóru ikki skrásett í Føroyum framm-
anundan. I báðum førum vóru tey á staðnum samstundis,
sum aðrir ferðandi náttfirvaldar róku inn higar. Hitin,
leiðin og ferðin á luftstreyminum bæði nær sjónum og á
850 nPa (1500 o.sj.), meðan teir ferðaðust, bendu á, at
bæði sløgini vórðu borin av luftstreymi, helst upp í 1000
m hædd. Verður leitað aftur til gomul veðurfrøðilig tøl,
kemur fram, at Agrostis segetum varð flutt úr Vestur-
evropa um eitt hátrýstøki uppi yvir bretsku oyggjunum,
meðan Noctua orbona varð flutt eystureftir úr Mið-
evropa um eitt lágtrýstøki, sum eisini var uppi yvir
bretsku oyggjunum.
Abstract
On 21 June 1996, a male Agrotis segetum (L.) was
caught at Oyrarbakki on northem Eysturoy and, on 7
July 1997, a female Noctua orbona (Hfn.) was caught at
Nesvík on northem Streymoy. The two moth species
had not been recorded previously in the Faroe Islands.
In both cases, their presence coincided with influxes of
other migratory lepidoptera species to the area. Tem-
perature conditions, the direction and flow rates of the
air currents both at sea level (s.l.) and at 850 hPa (1500
m a.s.l.) during the migratory periods of each indicated
that both species were transported by air currents, prob-
ably at altitudes of 1000 m a.s.l. Reference to meteoro-
logical “backtrack” data showed that Agrotis segetum
was transported from westem Europe westward via a
high-pressure area over the British Isles, while the Noc-
tua orbona was transported eastward from central Eu-
rope via a low-pressure area again over the British Isles.
Fróðskaparrit 47. bók 1999: 159-168