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Field sites of the projects
Dæli
The main field site for the tits studies is Dæli (59o 56' N, 10o 33' E). This site is located west of Oslo, just on the border between the western suburbs and the forest (see map). The study field spreads out over a south-facing slope, covering about 1.6 km2 of suitable habitat between the scenic lake Dælivann and Stein Gård, the farm to which most of the field belongs.
Most of the area is vegetated with lush broad-leaved forest, dominated by hazel, birch, maple, rowan, ash and elm. The rich vegetation is partly due to the favourable aspect of the slope, but also to the rich calcareous bedrock underlying the eastern half of the area. However, smaller areas of coniferous forest are also present. In the central areas pine is the dominating species, but Norway spruce takes over towards the northern and western edges, bordering the deeper forests of Bærumsmarka and Nordmarka.
As can be seen from the aerial picture at the upper right (click on an image to enlarge it), a road cuts trough the area and along this some scarce settlement is found. The study area is also bordering some large fields to the south, and also around the farm Stein Gård cultivated ground is found. Here, as in most of the forest, cattle graze during summertime. Unfortunately some of them have discovered how excellent our nest boxes are for scratching their backs... - luckily most clutches have fledged before the cows get to social!
In this area about 440 nest boxes are spread out, a number sufficient to provide a home for about every blue and great tit pair in the area. Each year only one or two pairs are found nesting in natural cavities. Also the pied flycatcher willingly makes use of the provided nest boxes, as do at least some of the nuthatches and coal tits breeding in the area.
Sørkedalen
Sørkedalen (59o 59' N, 10o 38' E) is the name of a valley reaching out from the suburban areas of Oslo into the deep forests of Nordmarka. Several field sites are located here, including Sinober, Tangen and Brenna, dating back to 1968 when the first nest boxes were put up at Tangen. Tangen consists of mainly spruce forest, whereas Sinober and Brenna have both mixed deciduous and coniferous forest.
At the moment these sites are not in active use by our group, as all ongoing projects are based at Dæli. However, the nest boxes are maintained and checked on a regular basis to obtain an overview over what birds are breeding there (especially to follow up and supply earlier earlier experiments in these areas with return rates etc.), and to band the young before they leave the nest boxes.
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