Breeding Marsh Harrier in Ayrshire

Angus Hogg

This article originally appeared in Ayrshire Bird Report 1998 and is reproduced here with kind permission of the Editor.

uring 1990 a pair of Marsh Harriers bred in South Ayrshire. Owing to the very public nature of the site, and the possibility of a return by the nesting birds, the record was not published at the time. Only a limited number of people were involved in watching the site (most of whom were directly involved with work involving raptors) and, details of the event were kept as quiet as possible. There follows an account of the events of 1990, largely made possible due to a detailed log being kept at the time by all those involved.

In the Beginning…

A chance remark by my daughter on the evening of 4th May that she had seen a "big brown bird being mobbed by crows" at Heart Loch as she was travelling to school, generated enough interest for the two of us to make a hasty evening visit to the site to check out my suspicions. After a brief wait, a pair of adult Marsh Harriers appeared and flew towards a spot in the reedbed near the road, copulation occurred. and the two birds settled down in the same area. Naturally, several possibilities suggested themselves as to what was likely to follow. Records of Marsh Harrier in Ayrshire had shown signs of an increase during the 1970's and 1980's, probably as a reflection of the national increase in breeding pairs. With the first occurrence of the species in 1952, there had been by 1990, up to 12 records, with 8 of these in the spring. In all but one instance, however, the records had occurred too late in the season for any realistic possibility of breeding to have taken place and, in any case, all records had involved singles. Now, in 1990, a distinct possibility presented itself for the first serious breeding attempt.

The Story Unfolds

Early the following morning I concealed myself in some bushes at the edge of the loch and waited to see what would happen. At 08.35 hrs the male came into the spot where he'd settled the previous evening with nesting material, mostly a collection of reeds. Both birds were present in this area till 10.45 when, to my amazement, a second female appeared high above the site. It circled the site for 10 minutes before disappearing to the south-west. Following this, the pair displayed for the next 50 minutes, gliding with lowered talons and making mock food-passes. The second female appeared again, briefly, at 19.23, before leaving once more to the South-west, never to be seen again.

During the following week further collection of nest material continued but the male occasionally took this into another spot at the back of the marsh complex, furthest from the road, raising the possibility of an alternative site having been chosen. By May 9th, though, it looked as if the pair had chosen the spot nearest the road, with most food items being brought into this area. Additionally, the female was most often seen to rise from this area. At the end of this first week I felt that there was sufficient evidence to suggest that the pair were at least attempting to nest, and contacted both the RSPB's Regional Officer in Glasgow and Dick Roxburgh of the South-west Raptor Study Group. An evening visit to the reedbed convinced us sufficiently, and it was decided firstly to speak to the farmer on whose land these events were unfolding, and secondly, to set up a watch with a limited group of volunteers.

At this point it must be said that we were exceptinally fortunate in both the interest and hospitality with which we were received by Mr and Mrs Wallace at Lochlands Farm. They could not have been more helpful and provided us not only with a concealed vantage point, but also another two pairs of eyes to keep watch. Roger Broad of RSPB arranged for the necessary paperwork for Dick and I, should a nest visit become necessary. So, we were now set for an intriguing summer.

The Waiting Begins

By the 13th it still was not absolutely certain that the site by the road had been chosen since both birds still frequented the second site at the back of the marsh. In fact much of the observed copulation occurred at this site until at least the 14th. However, the behaviour of the male who frequently seemed to be checking the roadside site, suggested that my initial suspicions were right. From about the 15th onwards things appeared to settle down and most of the female's food-begging calls were heard in this area and, by the 21st, the female definitely seemed to have settled on a clutch.

Between 30th May and 8th June most observations were of brief but spectacular food-passes between the pair, with a record on the 4th noting that she completely mis- timed her catch and had to retrieve the prey item from the reeds. The male's appearance in the nest site vicinity was always announced by a series of short, high pitched whistles, to which the female would often respond. His hunting forays did not appear to take him far from the site, suggesting that there was a sufficient food supply in the area - interesting in view of the nature of the surrounding land which is primarily one of mixed farming, the main cereal crop being barley. The furthest reported distance that he was observed travelling was 8 km when he was seen hunting at Threave Farm. Other reports involved sightings at Laigh Grange (6.5 kms) and towards Kilhenzie (2.5 km). He was frequently observed skirting around the edge of the south-west corner of the town of Maybole.

It had, by now, been estimated that the approximate date of hatch would be around 26th June and notes made at the time suggest that it might not have been far out. The female was seen collecting beakfuls of dry grass and taking it into the nest on 27th June and the male began to step up his visits with food. On subsequent dates, this pattern was followed with the actions of the male becoming a little more stealthy, often approaching the site at a much greater altitude and dropping in very quickly. On 6th July food-begging calls were heard from the reeds and the male took food directly to the nest with the female sitting in a low bush nearby. By the 12th, both adults were hunting, and food was often dropped into the nest, but it was also noted on this date that the female was acting very warily and didn't seem too keen to settle. A note on the following morning stated that Mrs Wallace had seen her hunting at 07.00 hours. This was the last time she was seen.

Crisis Management

The male's actions at the nest over the next two days gave sufficient cause for concern that it was even assumed that the nest had failed. The decision was taken, on the early afternoon of the 15th, to check the nest. A quick visit by Dick Roxburgh revealed, much to the relief of all, that a chick which was about three weeks old, was sitting on the nest. The question over whether or not the male would continue to supply the youngster was answered during the next few days with his redoubled efforts to bring food in often resulting in surprisingly quick returns - a five-minute interval between food drops being noted on one occasion. During the ensuing period the male also brought in nest refurbishment material and saw off any potential intruders, mostly Carrion Crows, which strayed into the area near the nest. By 25th July the male's behaviour indicated that further changes were afoot since he was now emerging from the reeds some distance away from the nest. Although he was still bringing in fresh nest material, it seemed as if the chick was now moving about in the reedbed. By the 26th it was quite clear that the chick was out of the nest and was into a secure, low roost site in a bush by the 27th. On the 28th the chick made its first tentative flights and was much more competent by the following day. During this period, most observers commented on the ease with which the male appeared to find prey from the surrounding area.

Success in Sight

With the male's continuing dedication, the chick continued to make good progress and, by early August was accepting food from him in regular food-pass manoeuvres. It was also noted that the male's arrival with food had become more secretive, frequently coming in low and, by the 8th, the juvenile was becoming more adventurous, leaving the neighbourhood of the marsh and exploring adjacent farmland. Although heavily reliant on the male, the young bird may have been hunting for itself by 12th August when it was seen to drop on to something in barley stubble and appeared to spend some time eating there. By mid August further reports mentioned the chick making what looked like kills but, although still heavily dependant on the male, there were indications that he was slowing down his kill rate in order to encourage the young bird to fend more for itself. Around 21st August there appeared to be a period when the male stepped up its supply of food to the chick since it did appear to be very hungry on occasion, maybe as a result of poor hunting success. By the 25th there was a bit more urgency in the chick's attempts to catch for itself, with hunting often taking place on the ground, the bird running and hopping amongst rushes after small prey items. Food provision for the chick continued until the 31st when the male left the area. The juvenile remained in the area until 3rd September, by which time a change to colder weather may have encouraged it to move.

The Whole Picture

During 1990 one other pair of Marsh Harriers successfully reared young in Scotland, making the Ayrshire record a "joint first" for Scotland, although there was an unsuccessful attempt in Aberdeenshire during 1980. However, remarkable as the Ayrshire record was in itself, the male's single-handedly taking over the rearing of the single juvenile was also very unusual, with two records quoted in recent literature. What may have made his task easier in this case was the presence of only one quite well developed juvenile. There was, nonetheless, a nervous two or three day period when the male had also to overcome and cope with the loss or disappearance of his mate.

One question which left watchers puzzled concerned the reason for the female's disappearance at such a late stage. She had already begun to feed the young bird (s) and seemed fairly settled. A possible answer may lie in a comment made by a farm worker at Lochlands who stated that he had seen at least one Fox entering the reedbed near the nest, perhaps attracted by the smell from the nest, or noises from the young birds. Another possibility may be that the female was a young and inexperienced bird, perhaps unable to cope with the nearby attentions of a Fox.

Identified food items brought in to the nest included mammals such as Field Vole, Brown Rat, Rabbit and other small rodents. A variety of birds also featured amongst the food items including Moorhen and a variety of small passerines. Food delivery was generally via food-pass during the early post-hatching period, the female taking the prey to the nest. However, the male's presence at the nest with a direct delivery became more frequent as the chicks grew older and the female started hunting.

The Story Since Then

In 1991 the male returned but, although he was not reported from Heart Loch, one sighting at nearby Chapelton Loch stated that he was present for at least three hours on the morning of 6th June. During 1992, what was undoubtedly the same male arrived at Heart Loch around the 29th or 30th April, staying until 5th May. He spent much of the time checking out the reedbed and revisiting the nest site but left at the onset of colder, wetter weather. In the same year a female also arrived at Heart Loch on 30th May, but this record almost certainly relates to a genuine migrant in view of the presence of other migrant species around this period. In 1994 a female was reported from Heart Loch on 25th April with perhaps the same bird being seen between Prestwick and Bogside from 3- 17 May.

Although not all sightings of Marsh Harriers in Ayrshire are reported, it seems clear that there is an upward trend of spring records. At least another 6 occurred during 1995, 5 of which arrived within a period which would have allowed for nesting. However, in 1996, only one was reported followed by none in 1997 and one in 1998. Elsewhere in Scotland, the species has begun to establish itself as a breeding bird and the number of spring migrants appears to be increasing. It would seem to be important, though, for several birds to be in the vicinty of a likely nest site during the last week of April if breeding is to be considered a possibility, and the events of April 1990 have not been replicated in Ayrshire since then.

Acknowledgements

As stated above, most of what happened at Heart Loch would not have run so smoothly had it not been for the kind hospitality and keen interest of Mr and Mrs Wallace. Additional thanks must go to other property holders in the area, notably Mr Sturgeon, Mr and Mrs Jess and Mr and Mrs Orr. Crucial to the success of such a scheme is the dedication of those who are prepared to spend long hours watching the site. Here, particular thanks must go to Dick Roxburgh, Charlie Park, Ricky Gladwell, David McIvor, Graham Mitchell and Peter McEwan. Thanks are also due to the following for helping out: Andrew Stevenson, Ian Miller, Chris Rollie, David Given, Bill Davidson, George Morrison and Gordon Riddle, with apologies to anybody whose name I've missed. It was a privilege to be part of this and, as Dick Roxburgh stated "the highlight of many years birding."

References

Rare Breeding Birds Panel

Rare Breeding Birds in the UK in 1990. British Birds (1992) 86, 72.

Clarke, R

The Marsh Harrier Hamlyn (1995) 54.

Murray, R

Scottish Bird Report 1996 Scottish Ornithologists' Club (1998) 23.