ESTIMATING POPULATION SIZES OF HERRING GULLS AT JOENSUU DUMP BY MARK-RESIGHTING DATA
2003, EURING Technical Meeting 2003, poster abstract 6.-12.10.2004 Radolfzell
The populations of Herring Gulls (Larus argentatus) at the rubbish dump of Joensuu were studied by population analysis based on mark-resighting data of 5 624 day-sightings of 657 colour ringed Herring Gull individuals in the year 2000. During the breeding season the total weekly numbers of gull individuals visiting at the dump were almost ten times higher than the maximum numbers of gulls seen present at any one time. The peak estimate at the end of April was over 12 000 individuals in a week (Popan5/Jolly-Seber/full). The counts of the birds present at the dump showed maximum numbers in October, when 2 000 Herring Gulls were seen at a time. However, the estimate for that week was only about 3 000 individuals. The total number of Herring Gulls visiting the Joensuu dump during the year 2000 was estimated to have been over 20 000 birds. In addition, the resident times and the timing of the migration of different age groups and sub-populations of Herring Gulls were studied. The results have been used in the management of gulls at the dumps. The population dynamics of Herring Gulls at the Joensuu dump will be analysed more thoroughly by using neural computing to analyse over 50 000 cr-sightings from the years 1997 - 2003.
The whole poster (305 kB) >> Juvaste, R. Estimating population sizes of herring gulls at Joensuu dump by
mark-resighting (read ringing) data
poster abstracts >> EURING Technical Meeting 2003, poster abstracts