Nesting site

The nest tree stands next to one of the torrents running close to the centre of a wooded side valley that descends from near the main peak down to the meadowland close to the main settlement.  The nest site is about two kilometres down from the peak, and the village a further one kilometre down.  At the level of the nest site the side valley is about 750 metres wide, from one bounding ridge to the other.  The site is essentially north facing.  The nest tree itself is a large Aspen Populus tremula, and there are several other similar individuals in the immediate area, but relatively few coppiced beech and oak.  There is no demand for aspen as fuelwood and these appear to have been left to grow on and, as a few have already done, to age and succumb to rot.

The nest and surroundings, post-breeding, September 2012

Perhaps in part because of the steep slope and the thin soil, but mainly because of the tree species composition and the rarity of coppicing, this particular site (probably under one hectare in extent) has a far more open structure at ground level than is typical in adjacent coppiced woodland.   There are far fewer ascending trunks to obstruct movement or vision, and each individual aspen tends to be of larger diameter and to attain greater height than usual for trees of any species in the coppiced woods.  Despite this relative openness, the wood floor is still well-shaded by the extensive leaf canopy level during late spring and summer.

The aspen bearing the nest is probably 18-20m high and measures 156cm in circumference at chest height (September 2015).  The nest is quite close to the top, perhaps around 15m, in a fork close to one of the main ascending trunks. The three nearest trees, all beech, have a circumference of 74, 72, and 117cm (respectively 1.8, 2.8 and 3m away from the nest tree), but generally on this slope the trees are much further apart. There are small sloping meadow areas within the woodland nearby.

The area is about an hour's climb uphill from the edge of the village, using a long-established narrow stony track.  The track passes at closest less than 100 metres from the nest tree, which is entirely invisible from the tunnel-like track when the trees are in leaf.  Up to the middle of the last century the track would have been used by ox-drawn wooden sledges bringing down hay or wood, but is now used primarily by small tractors when a patch of hill woodland above is being worked. The earliest part of the nesting season overlaps with the latest part of the usual woodcutting period, but cut wood may be collected at any point through the year.  On most days through the year there would be no tractors passing.  Two other similar tracks run on the other side of the nest area, midway up the valley side and along its crest; these are used more frequently, also by 4WD vehicles, but the lower of them is about 100m distant at closest. Recreational trail motorcycles use any passable track, usually in small groups, typically at weekends; these can cause extremely loud but transient noise.  Calls can sometimes be heard from woods immediately adjacent to these tracks, and once in early evening I saw a Goshawk perched in a tree overlooking a track.

People foraging for edible fungi are the most likely potential source of sustained disturbance in the immediate vicinity of the nest tree, but most such foraging activity is after the nesting phase is over, and with relatively few oaks or beech, the site itself does not seem to be a notable locality for truffles or porcini

For someone hoping to observe activity around the nest it often seems that the site was chosen solely to prevent this.  Remarkably, it is impossible to find a viewpoint on either slope of the side valley with a direct view onto the canopy around the nest site.  This is partly because the nest tree is next to a stream deep within the central trough of the valley so that trees growing along or a little above the stream margins invariably block the view. However, there are a few positions between 75 and 200m from the nest site, alongside rock outcrops in the woods or on meadow edges, where with patience and much luck, birds can be seen in flight shortly after they have left the nest site (the adult male in spring and early summer, or post-fledging juveniles in mid- to late summer).

Despite many many hours of observation from such positions  I have never seen a Goshawk arriving at the nest, and so suspect that the male bringing food typically approaches at or below canopy level.  The single occasion I saw a male carrying prey toward the nest was from a position about 150 metres downslope with trees on higher ground blocking any direct view of the nest area.  Birds appear to have easy access to open airspace downslope from the nest tree or the nest area more generally; this is the usual route taken by the foraging male when leaving the site.

In 2008, when I first (by chance) found the nest, it seemed remarkably large: I estimated one metre wide at the rim by two in depth, shaped somewhat like an inverted old-fashioned straw beehive. Despite its large size I would probably have walked right under it without noticing had I not been guided by the cries of a juvenile Goshawk.  A substantial part of the lowest part of the nest  appeared to have fallen away by the next spring.  The nest certainly varies in size and shape from year to year; twigs are dislodged by wind and storms and new ones are added to the top by nesting birds, often with green leaves.

This particular nest site conforms neatly with findings summarised by Kenward (2006, conclusion #3, p88): "Nests are typically in tall trees in stands of large trees, with ample sub-canopy flight space and low shrub cover. Nests are seldom close to woodland boundaries, but often with small openings nearby. Nest sites on slopes favour the lower parts, with cooler northerly and easterly aspects favoured in the south."

Kenward, R. 2006. The Goshawk. T & A D Poyser, London. (reprinted 2007)