Thursday, 7 April 2016

Goshawks 2016: early spring, a pair on-site again!

Goshawk leaving nesting site,
N Apennines, 1 April 2016
So different from the heat-hazed green slopes of summer, the north Apennines in winter can feel austere and unwelcoming, the naked contours of the land revealed through the leafless trees, sometimes layered with snow, sometimes showing only the pale brown carpet of dead leaves. But by late March, flowers of Cornelian Cherry (Cornus mas)and Italian Maple (Acer opalus) stand out here and there on the hillsides, patches of yellow and yellow-green  among the vast grey-brown expanse of bare beech and oak branches.

Already a bit late in the year, I was resigned to not seeing any Goshawk display flights (and never have done because every late winter visit so far has coincided with low cloud or rain or thick snow), but I still hoped at least to confirm the presence of Goshawks, and perhaps get some idea of the chances of nesting in the side valley used in several recent years.  To hear something would be fine, to see a bird would be great.

I arrived on March 30th to find the hills slightly brighter than the cloud-covered Po plains, with a few moments of veiled sunshine, but it was windy and cold as I set off uphill in the late afternoon.  Nothing seemed to be moving in the silent hills, and the weather was hardly uplifting, but after about an hour I heard a faint and slow "ke--ke--ke" from the centre of the valley ahead.  As I continued uphill, the calls became faster, more urgent, and then a female joined in: "wee-oo, wee-oo, wee-oo". The calling subsided as I reached my destination: the top of a small steep meadow enclosed in the woodland where the open slope allows a reasonable view over part of the tree-filled central axis of the valley, including the area where the Goshawks nest (the only Goshawk nest I've found in the area).  Although the nest itself cannot be seen, nor can the nest tree be picked out from this viewpoint, any calls in the vicinity can readily be heard and the birds themselves can very occasionally be seen in flight.  Any such views are unpredictable and usually fleeting (the adult male may be more active during nesting but seems mainly to arrive unseen below treetop height, and typically heads down the valley from the nest close to treetop height and does not appear in open airspace until a couple of hundred metres downhill).

Cornelian Cherry (left), Italian Maple, flowering in March 
As another spell of calling started, first slow, then more urgently, it was suddenly reminiscent of summer last year, listening to calls around food delivery or wails from young wanting food.  Then at about 19.00 hrs, as the weak late light lifted toward the higher slopes, the calling quite suddenly became more intense, faster and louder, so the single wailing cries of the female for a few seconds turned into a sustained "wee-oo-wee-oo-wee-oo", like an emergency vehicle siren.  I guessed this probably marked a copulation event, which can be noisy and very frequent in the period before egg-laying (see Cramp & Simmons, 1980, Kenward, 2006, and sources therein).

Even without sight of the hawks it is marvellous just to be certain they are there and to revel in the sense of wild nature their energetic calls evoke.  But crucially, I now knew that a male and female Goshawk were present, probably a mating pair, and they were in the precise area of woods where a pair has nested in several previous years!  That was the information I had been hoping to gain, so anything else would be a happy extra.

The following day (Thursday 31 March 2016) I headed up the opposite side of valley on the old track through the woods that passes at one point within about 100 metres of the nest tree (see "Nesting Site" page), then headed off at a right angle to the valley axis up to a small patch of landslip boulders within the woods.  This site does not give a view directly onto the canopy of the nest area but does allow a reasonable view of part of the airspace above it, and allows calls in the area to be heard clearly.  Typically a bird does not fly up straight from the nest but glides far downhill below or barely above treetop level before emerging briefly into view a couple of hundred metres away; such birds are very easily missed.

Distant, but certain Goshawk,
31 March 2016, N Apennines
There were a few relaxed "ke--ke--ke" calls through the morning, and a few short spells of wailing, but I had no clear idea of recent events at the nest when at 11.30 I caught sight of a distant raptor just breaking the skyline of the opposite ridge having apparently risen from the valley bottom some way downhill.  Looking slightly like a scaled-down Honey-buzzard in shape, quite long-winged, large tail fanned widely in turns and twisting one way and the other. Clearly a Goshawk, it stayed relatively low while moving up along the ridgeline opposite and then disappeared out of sight on the far side of it.  I would have bet good money that it had left the nest area moments before, glided a few hundred metres down-valley across the treetops and then started to climb, as the foraging male habitually did in previous seasons. The bird was distant when I first saw it but one tiny image shows a typical Goshawk shape, including the longer arm and narrow hand (relative to Sparrowhawk).

Silence until about 13.00, then more "ke--ke--ke" calls, then faster "kek-kek-kek", then some soft "wee-oo" wailing.  Calls gradually became more frequent until about 13.30, when a loud semi-duet turned into the same fast siren-like "wee-oo-wee-oo-wee-oo" that I'd heard the previous evening.  I guessed this was another copulation event.  Then about an hour later on my way back down to the village, I was next to the track on a slight prominence below which the ground falls away steeply toward the central torrent, and peering past the tree trunks into the open airspace beyond, when I saw a Goshawk gliding through the haze above the wooded depths of the valley, not yet distant and initially almost at my eye level.  Trying to track it as it moved in wide circles (appearing very leisurely but covering a lot of ground with scarcely a wingbeat) I soon lost it, obscured by the dense screen of bare branches rising from the slope below, but saw it for long enough to note a large bulge in the crop.  I could not tell the sex but wondered if this could have been the female, perhaps after consuming food provided by the male earlier in the day?

Friday 1st April, same location. Most cloudy with occasional weak gleams of sun, chilly. Two tractors were in a patch of thinned woodland on the opposite slope, noisily collecting logs cut last summer. Goshawk calls continued as before, with long periods of silence, then spells of low intensity calling, then sometimes louder and more urgent, sometimes apparently both male and female.  But I could not sense a definite pattern and could not visualise possible events in the nest area.  Then, with no hint of any interaction at the nest, a Goshawk was suddenly in the air above the site; it banked rapidly and flew fast but with few wingbeats downhill and out of sight beyond the wooded convex slope below.  I just had time to register the generally pale underside as it banked (ie. an adult bird) then grey-brown dorsally, a few dark tail bands, white alongside the tail base and a dark mask-like patch behind the eye.  Only managed one image before nearby branches got in the way.

Saturday 2nd. Similar phases of quiet and of calling. Mid-morning loud wailing calls and kek-kek-kek calls suddenly from trees close on my right but no bird visible and no bird seen to fly there. Confusing and frustrating! Then one glimpse of a raptor plummeting from that area toward the stream channel in mid valley. During the next hour there were just a few calls, apparently from a bird moving from tree to tree in the nest area, until a little after midday there was an excited "kek-kek-kek-kek" from the site and several seconds afterwards I just picked up a hawk heading for the nest site in a shallow but very fast dive from a point above the lower end of the valley. The bird at the nest site must have seen it approaching well before I was able to. It disappeared into the canopy, possibly a little way uphill from the actual nest site, without checking speed. I had never before seen a bird arriving at the nest site! I could not see if it brought prey, but there were soon spells of "kekking" and some wailing which accelerated to a shrieking crescendo, followed by silence...

So, a very productive visit: calls confirmed presence of Goshawks at the nest site, apparently a mating pair, with a couple of lucky sightings of birds in flight (and on April 1st I heard my first cuckoo of the year!).  If my calculations are correct, working back 75-80 days from apparent fledging around late June/early July in recent years, the female could even be laying during the next week.  Indications are that they may have already chosen to nest again at the known site.  Must not tempt fate but I am daring to hope that things turn out this way, and that I'll be able to listen and look for them at intervals over the coming months.

Cramp, S & Simmons, K E L (eds.). 1980. The Birds of the Western Palearctic, Vol II. OUP, Oxford.
Kenward, R. 2006. The Goshawk. T & A D Poyser, London. (reprinted 2007).