The Hen Harrier

by Donald Watson

  The surviving chick proved to be a male and, as it was clearly the larger of the two in the early stages, must have been the first to hatch. Balfour and Scharf found that the hierarchy in the nest depended on age rather than sex, although female chicks are as much as 100 grams heavier than males at fledging (Bannerman, 1953). We never knew the sex of the chicks that died, but our observations fit the concept of age hierarchy. Although it may be that the deaths were due to insufficient brooding by the female in the absence of food provision by the male, the following observations make this doubtful. The two chicks had been brooded for nearly an hour, in three stretches between 12.10 and 16.55, but a heavy rain shower when the hen was absent, from 13.15 to 13.30, might have chilled them. The chicks always appeared to be fed until they could take no more. This was particularly noticeable when large prey was brought, and a good deal was eaten by the female when the chicks were replete.

  On 25 July, a partly-eaten young Red Grouse was left in the nest for periods of 35 and 45 minutes, somewhat to the inconvenience of the surviving chick which could find nowhere to lie down. The chick sat for a long time at the edge of the nest with its vulturine head drooped over its distended crop and looked distinctly uncomfortable.

  In the latter part of its second week the chick became much more active when left unattended. Wing and leg stretching, which occurred fairly often, was a remarkable action, revealing the great length of a leg when at full stretch. At 22 days, on 31 July, feather growth on scapulars, wings, tail and ear coverts gave the chick a parti-coloured appearance and the dark feathered areas looked a little like a pair of braces across its back. Yet it was still predominantly downy at this stage (details of plumage and other changes in the growth of young harriers are given in Chapter 6).

  With the rapid growth of its feathers, the chick spent an increasing amount of time preening, probably mainly to remove loose down. The sun was hot on 31 July, and the chick passed the 2½ hours from 13.00 till 15.30 resting or preening in the shade outside the nest. In a site such as this, with plenty of tall trees and long heather close at hand, it was much easier for a chick to find shade than at some more open nests where bracken fronds may provide almost the only protection when the sun is high. Regular brooding of the chick was not seen after it was 2½ weeks old, but none of the later observations were made during periods of persistent rain.

  At 22 days the female, for the first time, was carefully feeding the chick small feathers from prey, and sometimes gave it quite large beaksful of feathers, gristle and bone. Louis even saw the chick accept and swallow both legs of a small bird, probably a young Skylark. The whole of this meal was demolished without trace within three minutes.

  On 2 August, when the chick was 24 days old, the female spent only ten minutes at the nest in seven hours (13.45–20.45). Her first appearance was at 17.00 hours when she dropped a plucked young passerine bird into the nest, without landing herself. An hour later she brought another small bird and fed the chick for two minutes. At 19.00 hours she fed the chick from two small birds, brought at the same time, for eight minutes. Jim’s chances of obtaining pictures were restricted to these final eight minutes. He took some pictures using flash and found that the bird was quite unconcerned by it.

  From the hide I had many opportunities of noting plumage details of this female harrier. It is probably true that no two individuals are precisely alike, while the same bird changes in details of appearance as the summer moult proceeds. This bird was growing her new outer tail feathers at the end of July and, in flight, these projected like little wedges half way along the tail. A new central tail feather was also about half grown and when she stood in the nest with her back to the hide the darker colour of this new feather was noticeable. Her wing feathers looked fresh, and certainly no flight feathers were missing or growing. I have seen female harriers, feeding young, in various stages of wing or tail moult, and have wondered that moulting should occur at a time when the bird requires to make its greatest efforts in hunting flight.

  For four days we did not occupy the hide. In a summer which will long be remembered for sunshine, the early part of August was exceptionally hot, with frequent outbreaks of thunder in the evenings. During my three and a half hour watch, from 07.50 on 7 August, the chick remained out of view, a metre or so from the nest. When the female landed at the nest with an un-plucked Skylark I expected the chick to run to her, but it did not appear. The female transferred the prey from foot to bill and moved out of my field of view towards the chick’s retreat. Six minutes later I heard her take off and I could only guess that she had been feeding the lark to the chick. Later that morning, Louis saw part of another Wood Pigeon brought—by this time the chick was back in the nest but the female made no attempt to feed the chick. When Louis left at 14.15, the pigeon still lay untouched in the nest, the 29 day old chick apparently not yet able to tear up such large prey for itself.

  On 7 August, while the chick was out of view, I took a long look at the fairyland pattern and colours of my little vista of anonymous forest. There was a cool beauty in the varied greens of spruce, pine and ling, the latter now with spikes of lilac flower. It was a morning of soft rain with beads of moisture at the top of every drooping sitka spray. The further trees receded into enclosing mistiness, full of the coo-ing of Wood Pigeons. A young, yellow speckled Robin and a Wren perched in turn, an arm’s length from the hide, apparently unconcerned by the harrier’s close proximity. Although the nest would have been very difficult for a casual human searcher to find, long vigils in the hide set the imagination working at times. Surely, I sometimes thought, someone will follow our tracks and emerge from the trees to blunder upon the nest, but, of course, no one ever did. I could even, occasionally, sense an uneasy feeling as though I had myself gone into hiding from unknown searchers. Such are the neuroses of hide watching deep in the forest. Mostly, however, there was no time for lapses of concentration as page after page of sketch book was filled and incidents noted.

  After leaving the hide on 7 August, I visited the site of the nest where there had been five chicks on 9 July. On the way I enjoyed a brilliant spectacle of eight or ten peacock butterflies on the tall heads of marsh thistles. Even more numerous in the lush rides were the dark, little Scotch argus butterflies, fluttering ahead of me at almost every step. As I approached the harrier site, one of the young, now more than six weeks old, rose in easy flight from the side of a broad ride.

  Up at the nest I collected a smelly assortment of prey remnants for later identification. As usual, at this stage, there were several fairly large pectoral girdles, but I could make only one immediate identification, from a foot of a young Red Grouse. Much of the prey had been smaller, judging from the accumulation of passerine feathers. Evidently, at the late stages, the young had been using the narrow extraction ride, a few yards from the nest, as a feeding place in preference to the nest itself. Looking at the much trampled nest platform, I was struck by its rather precarious situation at the very edge of a deep drain, which might have been hazardous for the chicks.

  There was nothing by the nest to suggest that any of the five young had failed to fledge, but a chance discovery in the ride, 300 metres away, proved that one of the female chicks (recognisable by its ring) must indeed have died in the nest. It had been dead for two or three weeks and the flight feathers, only partly emerged from their sheaths, could not have sustained flight. No doubt it had been carried away from the nest and dropped in the ride by the female parent which had evidently not fed it all to the other chicks. Why, I wonder, do harriers persistently drop their unwanted remains in the open rides, so laying a trail for any curious man or fox? One very obvious heap of plucked feathers was from a young Pheasant, but with Sparrowhawks feeding young in the tall larches nearby, there was no saying whether they or the harriers had accounted for this.

  On 9 August, Jim was tempted back to the hide for a final session of photography. This time the female had observed our approach and showed increasing aggression, making so
me beautiful, long dives at our heads with arched wings. The chick, too, was proving to be a bold character, standing his ground, quick to strike out with claws and bill, and even advancing a step or two towards us. It was now 31 days old and we were surprised to find that all the prey—three pipit-sized birds, partially plucked—was still being fed to it by the female.

  On the hot, sunny morning of 11 August, I was in the hide for my last watch. One day to go to the start of grouse shooting hardly more than a kilometre away! The young harrier was hunched like an eaglet in the ‘pathway’ from nest to hide as I settled in. It appeared rather grey-brown on its back and wings, apart from the pronounced russet pattern on the smaller coverts; and I wondered, not for the first time, if a comparison between a large number of male and female chicks would confirm a suspicion that females are browner, in their first feathering. Flies clustered on the wings and one leg of yet another Wood Pigeon in the nest. There was not much meat left on it. The narrow, fawn-brown tips to the unplucked wing coverts were a sure indication that this had been a young, fully-fledged bird. The pigeons could have been killed within 100 metres or so of the nest, and it was probably true that the late date of this nest meant that the female harrier had exceptional opportunities to prey on newly-fledged pigeons.

  Soon the chick was back in the nest, attempting to strip the remaining meat from the wing bones, but with little success. It evidently lacked the power in its legs to hold such large prey firmly and tear it with its bill at the same time. It played with the leg for a moment, as if about to swallow it, but dropped it again. The effort of trying to feed itself soon proved too exhausting and it sank on to its ‘haunches’. It looked awkward, even comical, especially when it turned its head to one side and gazed at flies with one eye; or, sometimes, to judge from its cheeping calls, at its female parent flying overhead. Sideview, the pale iris and an illusion of nakedness below the eye—caused by very short, russet feathers—gave it the facial expression of a domestic fowl. It still had a projecting tuft of down on the forehead, and more on the peak of its crown, forming an absurd little top-knot. Tiny shreds of down flew copiously from all the accessible parts of its plumage during extensive bouts of preening. The action of combing the still partly-sheathed tail feathers with the bill, was particularly neat. At times it stood on one leg, the other furled among the rich buff feathers of its underparts, and I was reminded of the old saying that ‘the harrier is lame and limpeth of one leg’.

  A renewed onslaught on the Wood Pigeon remains was more effective, after which it lay prone in the intense heat of early afternoon, the picture of ennui, with its head sagging sleepily forward. It was suddenly aroused, apparently having seen the female overhead. I heard the food call but could not decide whether it had been uttered by the chick or its parent. Later, it struck me that the call came perhaps from a fledged youngster at one of the other nests. The young birds were ranging widely over the forest and probably gave the food call to any passing adult.

  The hen did not come down to the nest and the chick’s excitement subsided quickly. Soon afterwards, the question of how it would rid itself of the down on its head was answered. Balancing clumsily, with a wing as prop, it scratched its head with a talon and the down began to fly. It was much more concerned by aircraft overhead than its parent had been, and Louis had recorded earlier that the chick had ‘a great fright’ and jumped into the air when a low-flying plane roared over. It was beginning to spend more time up on its legs, sometimes preening in this position, and wing exercising for the first time, bouncing well clear of the ground. Yet, though 35 days old, it did not look ready to make its first flight for another two or three days. As males are generally quicker to fly, and this one had often seemed surfeited with food in the absence of competition from siblings, I had expected a considerably earlier fledging date.

  At 15.00 hours I was due to leave the hide and had resigned myself to doing so without further sight of the female, but one final episode was enacted, swiftly and suddenly. The chick was in the ‘pathway’, skywatching. I heard a soft thump—something small had been dropped by the female between the chick and the hide. The chick reacted in wild confusion, hirpling first towards the new prey, then back into the nest without it, where it started to tug at the old bones of the Wood Pigeon, dragging them about like a dog greeting its master. The female pitched down beside it, seemed about to carry off the wing girdle of the pigeon, but dropped it again. In a few seconds she had gone, and the chick came down the pathway and retrieved the dropped prey from the heather. For my last few minutes I watched it competently tearing it up. When I came out of the hide, it had eaten all the hind parts from what proved to be a Meadow Pipit, brought in fully feathered.

  I came away regretfully, feeling that the 70 hours we had spent in the hide still left us much to learn about the early stage of a harrier’s life. The chick had survived one hazardous stage only to embark on another, even more hazardous, in the next few days. It had been reared, as far as we could tell, with little or no assistance from the male. It was due to fly at an extremely late date for a Hen Harrier, and was quite likely to blunder fatally among the guns on a grouse moor during the next few weeks. It has been calculated that 70% of young harriers die in their first year, so the prospects for a late fledgling in a fairly dangerous neighbourhood would not be rated highly. Yet, of course, I had a special hope that this young male would survive to return in a future spring, to ‘sky-dance’ over the forest, in the grey plumage of maturity.

  Postscript

  On 17 August, when the chick was 39 days old, I thought it would be well able to fly and that there would be no risk of it taking off prematurely if I visited the nest. All along the rides the heather flowering was at its peak and it was hard to accept that, so late in the season, a harrier could still be intensely protective of its young. The female indeed was more aggressive than she had ever been and, for the first time, I found myself ducking my head from her attacks. Knowing that fledged, young harriers often cling to the nest as their base, I ought not to have been surprised to find the chick still at home. It was on one of its favourite stances, a metre or so from the nest, upright, sphinx-like, its dark head now beautiful with all trace of down lost. Surprisingly, it did not rise as I came through the trees and I thought I might manage to examine the nest for prey without disturbing it, but as I bent down, it took off, yellow legs trailing, and flew rather unsteadily towards the nearest ride. Later, from a distance, I glimpsed it flying among the trees, probably returning to the nest, or thereabout. It had almost certainly made previous short flights. A couple of days earlier, a visit might indeed have made it fly too soon, with the risk of a crash-landing in an awkward spot.

  There was no trace of large prey by the nest but I found many feathers of small birds, some obviously of Meadow Pipits, and a young Robin lay partly eaten in the pathway. Although the Robin is one of the commonest small birds in the forest, and there had been many late broods this summer, I had not previously recorded it as prey.

  CHAPTER FOURTEEN

  Nest Sites

  All of the study nests were on the ground, and nearly equal numbers were found in fairly young conifer forest and on open moorland. None was found in forest rides.

  Heather, Calluna vulgaris and Erica spp, was much the commonest dominant vegetation surrounding nests, both at forest and moorland sites. At more than half the moorland nests, bracken grew among the heather and provided additional shade and shelter for chicks. Some sites had a mixture of heather, Molinia (purple moor grass) and/or bog myrtle, often with bracken as well. Heather was absent from only three sites, one in almost pure Molinia, one in rushes Juncus sp and another in Molinia among young conifers. Most moorland nest sites were in fairly deep ground cover, 60–100 centimetres high or more, but a few were in very sparse cover. Such rather poorly concealed nests on moorland often failed. Two nests, in one season, in fairly short heather (about 60 centimetres high) failed early, in spite of being distant from any roads; and the most open
nest of all, in pure Molinia, failed after hatching.

  Forest nests were always well concealed in the very lush ground vegetation, frequently more than a metre high, which was a feature of the young plantations. Heather was generally dominant, with a strong admixture of Molinia and bog myrtle. The height of the surrounding conifers varied greatly, from about 1.50 metres to over six metres. The harriers showed a marked preference for the more open parts of the forest, where tree growth was retarded, sometimes due to early browsing by deer. All forest nests were in plantations at least five years old. In Area C it appeared likely that the difficulty of finding sufficiently open sites was a reason for the reduction, and possible cessation, of nesting after the trees were about 15 years old; but in Area E, in 1975, there were three nests in 14 year old forest, where only one had been found in any previous year. In such older plantations, we were often aided in the final search for a nest by the knowledge that it was almost certain to be in a patch of ground where the trees were comparatively sparse or stunted.

  The most common tree species in the forest were sitka spruce Picca sitchensis and lodgepole pine Pinus contorta. All the forest nests were found where these two species were mixed, but there was some evidence that sites with a good proportion of pine were favoured. Blocks of larch Larix sp were quite widespread, but no nests were found amongst them, probably because this tree rapidly forms a close canopy. The unevenness of tree growth in plantations of spruce and pine facilitates landing and taking off at nest sites, as well as providing space for the nest itself. These conditions may continue in blocks of trees more than 15 years old, which at first glance look far too tall and dense to be suitable for nesting. Even when Hen Harriers are nesting on open moorland, both sexes make use of prominent perches nearby, either rocks or isolated trees, and it seems likely that the fairly high perching-places provided by the top branches of 10–15 year old forest conifers are an additional attraction. Females with young very often use trees as look-outs.