Individual study: Comparison of use of shallow and deep nest boxes by tits Parus spp. at Garten Wood, Abernethy, Inverness-shire, Scotland
Summers R.W. & Taylor W.G. (1996) Use by tits of nest boxes of different designs in pinewoods. Bird Study, 43, 138-141
In the British Isles, the crested tit Parus cristatus is restricted to Scotland where it is an uncommon and local species confined mostly to Scots pine Pinus sylvestris forests. Three common and widespread tits, coal tit Parus ater, blue tit Parus caeruleus and great tit Parus major, regularly use nest boxes but crested tits do not. This may perhaps be because the nest box design is unsuitable. Studies were therefore undertaken to design a suitable nest box for crested tits which generally use rotting tree stumps in which to excavate a nest cavity. In one experiment, (see Case 152) given that crested tits excavate their own nest cavity, boxes were part-filled with sawdust and wood-shavings to see if this enhanced crested tit nest box uptake. In a second experiment (described here), uptake of two different nest box types (shallow and deep) were compared in a pine woodland in Strathspey, northeast Scotland.
Study site: The experiment was conducted at Garten Wood (a thinned Scots pine Pinus sylvestris plantation), Abernethy in Strathspey, north-east Scotland.
Net box design & placement: In January 1991, nest boxes of two different designs were erected in pairs (at a height of 1.5 m, on similarly sized trees a few metres apart, at a similar aspect) at 18 sites in Garten Wood. The two designs were:
i) 'Shallow' boxes - shallow nest boxes (11.5 cm long x 10.5 cm wide x 15 cm deep, entrance hole diameter 33 mm its centre 5 cm from the top of the face of the box)
ii) 'Deep' boxes - deep nest boxes (12 x 8 x 25 cm deep, entrance hole diameter 33 mm its centre 5 cm from the top of the face of the box)
All nest boxes were new at the start of the experiment and therefore free of fleas. During the breeding season boxes were regularly checked for nest lining and eggs.
A total of five deep nest boxes out of the 18 deep boxes available were occupied and eggs laid, all were great tits. Non of the shallow boxes were occupied by any species.
Conclusions: These results, taken on there own (see also Case 153), are rather inconclusive due to the small sample size, low uptake of boxes and short duration (only conducted over one breeding season) of the experiment. The results do however concur with other studies that show that great tits have a preference for 'deep' nest boxes. Crested tits used non of the 36 available boxes, regardless of depth.
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