Thursday 28 July 2016

Juvenile Goshawks flying free!

One of the two juvenile Goshawks, 25.vii.2016, N Apennines
In the previous post I mentioned that I hadn't been expecting juveniles flying free above the woods for some days yet, simply because last year it was about a week into August before I saw one.  On the 25th I went again to the narrow ledge at the top of a rocky outcrop on the valley side downstream of the nest area.  The site itself is not visible from that 'edge' watchpoint, but the valley downstream extends left to right (north) immediately below the edge, and the male typically flies (like a rocket through the treetops) down this section of valley after a food delivery.  I went along there mid-morning again, hoping that I might by a stroke of good fortune coincide with a food drop and get a chance of seeing one of the adults.

juvenile Goshawk, 25.vii.2016
For about an hour and a half there was just a sporadic juvenile Goshawk cry, similar to the adult wail but weaker and higher in pitch.  At first, each set of three would be separated by 10 or 15 minutes, but abruptly and for no visible reason, the gap shortened and then there was a flurry of excited calling from at least two birds together.  I was on the alert in case an adult had just brought food and would be visible leaving the site, but instead the calling got louder and even more urgent, apparently closer.  Then I caught side of a Goshawk flying quickly up from woods downstream of  the nest site, at first close to the foot of the far slope of the valley, then higher and out into the open airspace above the valley and in front of my watchpoint.  It had the streaked breast and slightly more delicate appearance of a juvenile, and was promptly followed by a second!

With almost continuous calling, the two Goshawks dashed around the area right in front of me, sometimes apart, sometimes chasing and grappling with a sudden flash of underwings and spread tails, gradually  spiralling wider and higher.  One would often come within about 20 metres of my position, half-hidden by the overhanging leaves from the wood at my back.  The fast-flying hawks above, the wild shrieking calls: all this and a summer's day in the green hills!

juvenile Goshawk, 25.vii.2016, N Apennines
After a couple of minutes the two moved away over the woods behind, still calling, then returned, then as they moved away behind again, their calls became fainter and stopped.  I waited a long time but didn't see them return, and don't really know if they had already returned to the nest site from a different direction or had moved away for  wider exploration.  I strongly suspect, but don't know for sure, that this was their first extended flight above the canopy; I've visited the watchpoints around the nest area often this month, and have only heard evidence of juvenile movements within the woods, ranging between an estimated 200 metres upstream from the nest tree and 200 m in a downstream direction.

For concentrated excitement, and sustained proximity to wild raptors in flight, I can't imagine those minutes will be surpassed.  It was deeply satisfying because I've spent too many hours trying to keep in touch with key events at this nest, listening for calls and looking out for Goshawks in flight in the valley.  And too many hours worrying that someone will disturb them, or that another night's torrential rain or leaf-shredding hailstorm would be one stress too many, or that the male will not be able to keep the food supply going, or that a fledgling will fall from the nest.  Of course it's somewhat absurd to get personally involved, but there it is.

Perhaps it was so moving because this year I've been lucky enough to follow events from late March, when the adults were starting to reoccupy the nest site, and mating (often, judging by the bouts of increasingly frenzied calling), right up to the juveniles flying free above the canopy (there might be a third to make that step, perhaps significantly younger, judging by the thin calls still coming from the area when the others had flown off).

Monday 25 July 2016

July 2016, progress report

Distant Goshawk heading for the ridge, 16.vii.2016
So, back in the Apennines since 9 July, and the first unpleasant lesson has been that it is now very much more difficult to see the male Goshawk.  Not really sure why this is.  Presumably the female is now hunting more for herself and the young, and now that this responsibility is shared, the male does not need to be rushing around in such conspicuous haste.  Perhaps the female spends even less time flying in open airspace above the woods than the male does. It may also be that the female tends to be less protective of the nest once the young are flying within the wood, so the male is perhaps under less pressure to keep his distance.

It must be safe to assume the young have fledged, because since arriving back I have heard their relatively 'thin' wailing calls from different points within a couple of hundred metres radius of the nest.  I have not yet seen one in free flight above the woods this year; last year they did not appear in open flight until early August.

But I did see one in the woods by accident a couple of days ago.  I was on the trail that goes up the valley and passes quite close to the nest tree (the nest can just be seen from the trail in winter when the trees are bare, if you know where to look).  The trail loops around above the site and crosses to the other side of the valley, but above the site the loop crosses the same seasonal torrent that then flows down past the nest tree.  In fact, it is almost bone-dry this July (baking hot in contrast to wet and chilly June).  A juvenile Goshawk must have heard my approach because it flew up, with a cry, from the bottom of the deep and narrow torrent bed just below the trail.  Peering down I saw that a couple of tiny pools remained, dammed up behind boulders; the bird had been out of sight but must surely have been next to the water, presumably drinking.  It was certainly a young juvenile, dark sooty brown dorsally and very raggedy in appearance, but easily able to take off from a constrained space and slip away between tree trunks to somewhere near the nest, where it wailed again a couple of times, provoking a sibling (or two) to join in.

I was sorry to have disturbed it, but confident it could return to the water if needed, and very happy to learn that at least one of the brood is now able enough to take off from the ground.  In late July last year, returning from a period at home, I found remains of a near-fledgling Goshawk (flight feathers still emerging) that must have fallen to the ground, or been blown from the nest, and been unable to take off again.

Over several days since arriving back (not quite so many hours total observation time as in May-June) I have only twice briefly seen an adult.  A few days ago I was in fields at the lower end of the valley, close to the village, trying to pick up any Honey-buzzard flight over the panoramic expanse of woods above, but instead saw a Goshawk fly fast over the treetops of the wood bordering the upper meadows, and cross the valley to the ridge on its western side.  It then followed the ridgeline up towards the mountain at the head of the side valley, pausing to repeatedly circle a couple of sections, as if looking closely for potential prey (composite image below).  This is the route most commonly taken by the adult male after leaving the nest area, and it was in one of those sections the bird was examining, where coppicing has left a micro-mosaic of wooded, bushy and open patches of ground, that I once saw a Goshawk perched early one autumn evening.

Adult Goshawk foraging. Composite image to show aspects of flight shape (not plumage detail!) and a little landscape for context. Note long-winged appearance, broad secondaries almost 'stepped' up from the narrow hand, and very conspicuous white 'flashes' (lateral undertail coverts) that seem to be prominent at all times in the breeding male (not sure about other periods).  N Apennines, 16.vii.2016
Then yesterday I was at one of my old watchpoints, that has a view of the valley downstream of the nest site, listening hard for the sporadic calling of juvenile Goshawks (slightly distracted by an occasional distant Honey-buzzard whistle-call, and the screeching of a Peacock kept by someone in the village below).  About a minute after a short spell of agitated wailing, apparently from two juveniles, unseen but not far below, an adult came fast down the centre of the valley, turned a couple of relatively wide and slow circles over a patch of cut hay-meadow, and vanished again into the woods.

Saturday 2 July 2016

Flight direction of the male Goshawk leaving the nest

Male Goshawk gaining height at the start of a
foraging trip after leaving nest site, probably
heading for the first ridgeline or the valley
beyond. Note white undertail coverts either
 side of tail. 10.vi.2016
I left the Apennines on 21 June and have since had opportunity to reflect on my attempt over the past few weeks to get more familar with Goshawks.

Quick recap: I found the Goshawk nest by chance in 2008; it was used by a Common Buzzard in 2011, and by Goshawks certainly for six of the seven remaining years (no data for 2009). That's 7 out of 9 years up to and including 2016.  My main hope for 2016 was that a Goshawk pair would again use the known nest and breed successfully.

Visits in March-April confirmed that an adult pair were active at the site and, having listened closely to vocalisations from the nest area in June, I believe that when I left the valley the pair had produced at least one near-fledgling (making wailing calls noticeably 'thinner' and quieter than the adult).  It might become clear later (plan to return mid-July) if there is more than one juvenile, but an accurate count will not be possible just by listening for calls.  If last year is any guide, juveniles may be expected occasionally to fly above the canopy from late July onward.

Given a nesting pair, my next priority was to observe from the few locations on the surrounding wooded hillsides, such as the edge of an old meadow or rockslide, giving some view of the wider landscape and of the airspace above the nest, in the hope of seeing the male more reliably.  I also wanted to try and get some decent images, less distant than hitherto.  As noted in the intro pages (see "Nesting Site" page) there is no view down onto the canopy of the woods where the nest tree stands; closer trees block any direct view from all watchpoints in the surrounding area, but the airspace above the nest site and up and down the valley in which it is situated can be scanned.

Male Goshawk moving along the far slopes of the nesting 
valley  at the  start of a new foraging trip after leaving 
nest site.  Note white undertail coverts and 
bulging crop.  13.vi.2016
It's OK to hope, but best not to have expectations, and essential not to be in a hurry.  The cool rainy or stormy weather throughout June meant that sessions were often abandoned, or I didn't even leave the house, and because of the apparent scarcity of other raptors this year, I spent countless hours trying to stay alert while gazing at wooded hills and an apparently empty sky.  This has its charms, but can pall after a while.

But I did get to see the adult male several times.  The usual course of events was that I'd suddenly hear a loud "kek-kek-kek" call, perhaps a couple, perhaps with one or two "wee-oo" wails, then I would become hyper-alert for the male in flight.  Typically, very soon after the calling (a few seconds or couple of minutes), he would streak away downhill among the treetops in the centre of the valley, parallel to the main torrent in its deep-cut channel.  Variations in the height of trees along the valley might give me a lucky glimpse of him in flight, but often I would only pick him up once he'd travelled 750-1000 metres downslope from the nest site and turned back to fly diagonally up the opposite valley slope and back along the crest, past the nest area and toward the higher woods.  Sometimes, instead of doubling back and zig-zagging up along the crest, he would soar upward, usually fast but sometimes more relaxed, and move off toward nearby hillsides.

Twice he appeared to head straight up the valley slope opposite my usual position before turning to move uphill parallel to the crest, and three times he moved in the opposite direction, more or less toward my usual position and the out of my sight over the wooded slopes behind me. A couple of times I first saw him higher up the valley after an apparent food drop; I don't know if he headed this way straight from the nest, or if he'd taken the usual downhill route and I had failed to notice him before he'd worked his way back up the valley.

The map below attempts to represent this information.  Essentially, he usually leaves low or very low in fast direct flight down the centre of the valley, he will then usually turn to his left (ie. west) and move up over the far slopes of the valley, often directly over the ridge crest, toward the higher outcrops to the south.  Sometimes he would drop down on one side then the other (something like a scaled-up Sparrowhawk zig-zagging along a hedgeline); often he'd move across to the far side and not reappear.  During my observation times he left by this route more often than all the other routes indicated combined.

Sketch map to show initial route of male leaving the nest site. Red dot indicates location of nest; orange arrows represent flightpaths, their width indicates frequency (ie. the male most often leaves down the centre of the valley).  Green lines are contour lines at 100 metre intervals; the land slopes from south to north and rises to over 1400 m beyond the lower left (southwest) corner of the map. Grey bands suggest main ridge features.  Dashed blue lines show hill torrents, draining in general to the north and east. The three green stars indicate location of main observation points (the eastern point on the 800 m contour is the one I most often use). 
There is a location along that ridgeline where trees overhang a stone trackway and patches of partially coppiced woodland; I have several times heard a Goshawk alarm call here and once, at dusk, briefly saw a bird perched over the track that could only have been a Goshawk.  I suspect this is the kind of terrain that the male would often perch on the lookout for prey.

His most frequent departure route means that he is at minimum 700-800 metres away by the time I see him, ie. I have lots more images of a distant male Goshawk.  On the rare occasions when he left low over my position, his much greater relative speed meant that my camera (unsuitable for birds in fast flight) could not find focus before he was out of sight over the woods behind me.  Cue expletives.

Once, I had been in position for a couple of hours, and had just put my camera down and picked up a pencil to make some notes; at this moment the male abruptly rose up from the nest woods and flew directly overhead giving me just enough time to grab only one nearly sharp image (crop shown in the previous post, but here's the image again, below).  There had been no sounds to indicate he'd just delivered food; I guessed that he'd been resting in the vicinity of the nest site since before I arrived in position, having delivered prey some time earlier.  Several images of the departing male show a distended crop showing that he had consumed some of the prey he'd brought.

The breeding male leaving overhead after a food delivery, N Apennines, 30.v.2016 
It is exceptional to see the male arriving and I infer that he typically does so under or within the woodland canopy.  I have only once seen him arrive at the nest area in open flight during the season so far, and only once in previous seasons.  One morning in June I was just getting organised among the broken rock of the old landslip when I heard an unfamiliar, slightly 'croaky' call, and a bird swept past from behind the treetops close on my right. I did not immediately realise it was the male Goshawk, partly because of the call and partly because the flight was unfamilar, with something of a 'fluttering' action: perhaps he was carrying heavy prey (I did not see prey) or could it have been a signal to the female (never read of this, so presumably not).  He flew in a straight line to a point upslope of where I estimate the nest to be located, then a sharp turn downhill and fast descent below the trees in front of my position.