Mistletoe Winter

Roy Dennis

• Publisher: Saraband
• Year: 2021
• Print ISBN: 9781913393250
• eBook ISBN: 9781913393267
• Topic: Scienze biologiche
• Subtopic: Conservazione e Tutela dell'Ambiente

A new collection of vibrant essays to inform, stimulate and inspire every nature lover.

Times of darkness offer opportunities to reflect. In Mistletoe Winter, Roy Dennis offers his reflections on the natural world from the past year – from the welcome signs of change to the ongoing problems we are posing for nature, and what humankind can and must do about them.

As in his companion volume, Cottongrass Summer, Roy Dennis balances his alarm at the crisis confronting the natural world with his own sense of optimism that new generations can make crucial changes for the future. One of our most prominent advocates for our planet and its species, he writes with insight and originality. This volume will provide inspiration and ideas for everyone who cares about our planet and its species.

73

Summer

74

An octogenarian dangling from a rope

At my home in the Highlands of Scotland, tucked safely in a drawer, is a simple wooden pulley. The rope long rotted away, it’s a memento of a great man and an extraordinary eagle eyrie, and it reminds me that some of the work we do with wildlife, which we might think of as ground-breaking, has been carried out by others before us.

Forty years ago, I was doing a lot of fieldwork on golden eagles, especially in the glens of north Inverness-shire and Ross-shire. I knew I was missing a nesting pair in Glen Affric and could not find where they were breeding. There was a lovely period of weather in early May, so I hiked up through the woods one early evening, allowing me to scan the whole glen in the lovely evening light. That night I bivvied under a tree near the top of the glen, so that I was on my way soon after dawn, searching the woods. I disturbed an eagle from a group of old Scots pines, so I walked into the group of great trees. Droppings, pellets, moulted feathers, fresh down and some red grouse feathers told me immediately that I was in the right place, and that eagles had been using the wood regularly for roosting. Another hundred metres further on I looked up into an ancient Caledonian pine and saw the huge nest I’d been looking for.

It was a golden eagle eyrie that was not on our maps, and it was in use. I was really pleased that I had filled in a missing part of the jigsaw of contiguous home ranges in the Inverness glens. But when I got to the bottom of the tree and looked up, I saw to my amazement that the nest was built on top of big spars of timber. Who had built this nest? When? And why?

I sought out my friend Don, the forest ranger, and after racking 75his brains he remembered that in the 1930s, when he’d been a boy, the legendary eagle-watcher Seton Gordon had called on his father, who worked on the estate. Seton had known that eagles’ eyrie for some years and had just found that the main branch had broken under its weight, sending the nest to the ground. With the help of the locals, they had fixed in two big spars to replace the broken limb and rebuilt the nest. Since that summer, it had been in use, on and off, for half a century.

Some months later, I returned with two friends to ring the eaglet. We found, hanging above the nest, the original wooden pulley used to pull up the timber. A few summers later, on another visit to the eyrie, I found the pulley on the ground, as its rope had finally rotted. I put it in my pocket, a precious souvenir.

But it’s not a souvenir of times past. That story has been repeated, in various forms, in various places, throughout my working life.

In September 2020, golden eagles were reported to be breeding successfully for the first time in living memory at the Dundreggan reserve, owned by the charity Trees for Life. The story soon became news worldwide, but it had begun ten years earlier.

On 30th June 2010, I had driven north with David Clark and Ryan Munroe, of Alladale Wilderness Reserve, to the RSPB Forsinard Reserve in the Flow Country. The manager, Norrie Russell, took us some of the way in a cross-country Argocat before we walked across the hills to an eagle nest with two big young. We were there to fit satellite transmitters, as part of our eagle studies. The eyrie was on a small cliff overlooking the typical Flow Country landscape of peaty lochans dotted across a vast area of deep peats. We ringed both young before returning them to their eyrie, transmitter 57107 on the young male, 57106 on the female. We had a great walk back in the evening sun and I finally got home at midnight after a wonderful day’s fieldwork. 76

The male eaglet left his parents and his natal home in October and ranged widely, but the female stayed with her parents until after the New Year. During his wanderings, the male arrived at Dundreggan on 17th November 2010 and roosted there overnight in a cliff, before heading north the following day. This is part of Glen Moriston, which runs north and west of Loch Ness. It was an area I knew well in the late 1970s and 1980s when I monitored golden eagles in the Highlands. In those days, though, the glen was a blackspot for the illegal persecution of large raptors, so the ancient breeding sites were unoccupied. By 2008, Dundreggan Estate had been purchased by Trees for Life, during a period when I was one of their volunteer board members.

During the collection of satellite data from over twenty eagles, I had noted that many chose to visit long-abandoned nesting areas, and this led to my suggesting to Alan Featherstone Watson, the founder of Trees for Life, that we build a nest on the new reserve. In October 2015, I went to Dundreggan and explained to the staff how to build an eagle nest, before we headed to the site. Using my binoculars, I searched the line of low cliffs from a distance and saw one place that looked suitable for building an eyrie. It also matched the GPS location on my map of the eagle’s overnight stay in 2010. Alan had asked a local climber, Ewan, to come with his climbing gear, and after fixing ropes, he and I abseiled into the best ledge. To my amazement, the overgrown ledge contained the ancient stick remains of an eagle eyrie, probably from the middle of the last century. I cleared the ledge of vegetation, including a small conifer that was blocking access, before we hauled up bundles of sticks tied to our rope by the group of helpers below. Arranging the sticks, adding moss and grass and, finally, a topping of leaf litter resulted in a good starter eyrie for prospecting eagles.

Doug Gilbert, the manager of the reserve, reported an eagle over the cliff that winter but it was not until August 2020 that I 77heard the exciting news that a pair was rearing a single eaglet in our nest. He reported that they had built a big structure on top of our original nest and it is very likely that they had started taking an interest in the ancient breeding site the year before.

This is an exciting development and demonstrates that eagles will successfully return to ancient nesting places when illegal persecution is stopped. Sometimes they do it by themselves, and sometimes they do it with our help. I love that these big raptors build up histories, with eyries used for centuries and some individuals living very long lives. Five years may seem a long time to wait for successful breeding, but we have built nests in other good places and are still waiting for them to be occupied.

For Trees for Life, it is a tribute to their management of their rewilding reserve, and there’s every likelihood that this pair will decide to stay and become regular successful breeders. The global interest was very encouraging and gave us a chance to point out that the success of this pair is part of the ecological restoration of degraded lands: this nest is an icon of restoring nature. And it’s created some great headlines – my son-in-law messaged me to say that he particularly liked the caption below one of the newspaper photos, describing me as ‘an octogenarian conservationist dangling from a rope’.

78

Nature’s woodworkers

The simplest things, which all of us can see whenever we walk through woodland, can tell us the biggest things about evolution on our planet. Take woodpecker holes. Just as a woodworker might select the right drill bit for a particular job, nature provides a range of different sized woodpeckers, making different sized holes in trees. At one end of the scale in Europe are the tiny lesser spotted woodpeckers, making holes of just three centimetres in diameter, while large black woodpeckers have a nest hole of more than three times that in diameter. I’m not sure that you can talk about altruism in the animal world, but someone should tell the woodpeckers how special they are as a keystone species.

There used to be a distinctive clump of dead Scots pine trees near where I lived in Abernethy Forest in the Scottish Highlands. I think they had died because a little river nearby had become blocked, the water spreading out to create a small marsh around their bases, finally killing them. They reminded me of similar clumps of dead trees in beaver-dammed ponds elsewhere. Looking across the hundred metres or so to this group of trees, it was clear that the trees were dotted with great spotted woodpecker nest holes. This is a species once thought to be extinct in Scotland, a note in the Victorian-era bird books suggesting that there may have been just a tiny population of less than a handful of pairs hanging on in that very same Abernethy Forest. But things have changed since then.

These present-day holes were always worth a look in spring and early summer, for as well as finding young woodpeckers calling loudly from their nest, I could discover one or two of the old holes being used for breeding by swifts. It was absolutely lovely to 79watch and hear them dashing through the open forest and across the bogs, swooping up and into one of the old holes. Twice in the 1970s, a very rare breeding species called the wryneck also chose to live there, for they like to lay their eggs in vacant woodpecker holes. One year there was just a single male perching at the very top of the dead trees, incessantly giving its ‘pee-pee-pee’ call, while in another year a pair of wryneck nested.

Before swifts lived in the roofs of our buildings and became a familiar sight in towns and villages, their original haunts would have been holes in trees, often excavated by woodpeckers. Many years ago, when the famous cameraman Hugh Miles was making a film with the RSPB on the birds of the native pinewood, he was filming, from his hide, a pair of great spotted woodpeckers feeding their young in a nest hole in the same forest. Their red-topped heads stuck out, waiting for the food-carrying parents, and what a noise they made! He filmed on the day that the young woodpeckers fledged and left their nest chamber, and was amazed that, within very little time at all, a pair of swifts flew down and dived into the hole. The swifts must reconnoitre the forests, checking out dead trees and almost certainly selecting the holes being used to rear that season’s brood of woodpeckers. These will be the best nest sites, with possibly the lowest burden of parasites.

Holes in trees, as well as being really important nesting and roosting sites for a variety of bird species, are also important for mammals such as bats and invertebrates such as bees and wasps. In the ancient forests before man made an impact, cutting down trees for timber and firewood, there were of course many more non-excavated holes caused by damage and disease during the lifetime of individual trees. Some of those would have been major cavities, capable of holding bat roosts, breeding tawny owls and even larger creatures. The cavities in those eras may have outnumbered woodpecker holes but nowadays, in our managed 80woodlands, natural holes are surprisingly scarce, meaning that woodpecker holes are very important. They also last for many years and plenty are available for use for several decades.

Nowadays, in Britain, we can get over the lack of holes by building and erecting nest boxes of all shapes and sizes and with hole sizes carefully tailored to the species of interest. In the 1960s, I put up large nest boxes to encourage goldeneye ducks to breed in Scotland, which led to me meeting ornithologists in Sweden who were studying the same species. Many of their birds, though, were breeding in the holes created by black woodpeckers. I remember being amazed when one of my Swedish friends pointed to a hole in a live aspen that must have been sixty feet above the ground. It was regularly used by goldeneye, and the young ducklings must have had an exciting first view of the outside world as they jumped out and floated to the ground.

That first visit to the northern forests also showed me places where different species of owls were nesting in different sized woodpecker holes. One tree I will always remember was a live Norway spruce with two small woodpecker holes, one at about a metre from the ground, the other one twice as high. My friend smiled and told me that, in years of deep snow, a pygmy owl would use the higher one, while in years of less snow it might use the lower one.

Woodpeckers generally make a new nest each year, which is beneficial to the other birds that use these nest cavities, with a supply of new nest holes always available. This is almost certainly important from the point of view of predation, for many of these hole-nesting birds can be predated by pine martens in the larger holes, and by stoats and weasels in the lower, smaller ones. The people in Sweden that I met in 1979, when the small population of goldeneye ducks breeding in my nest boxes in Strathspey was increasing, told me that the worst predator was the pine marten, 81which at that time was absent from my study area. In their studies on the goldeneyes using black woodpecker holes, they found that nearly three-quarters of the nests in the new woodpecker holes were successful, but that only one third succeeded in nest holes that had been around for several years. Now that the martens have again spread across Scotland, I understand clearly what they were talking about. The martens certainly learn and remember the location of nest boxes, to raid them for eggs or young, even killing the adult ducks. Move the boxes around into new places each spring, though, and the ducks have a greater chance of success.

Black woodpeckers are common in the woods of mainland Europe but have never crossed the Channel to colonise the British Isles, so big woodpecker hole nesting sites are not available in our country for larger birds like stock doves and jackdaws. They need to find non-excavated sites, but over a dozen species – including starling, redstart, nuthatch and various tits – nest in the old cavities made by the three British-occurring woodpeckers. Starlings have decreased and the lack of competition for nest sites is thought to be one of the reasons great spotted woodpeckers are doing so well, but I have always suspected that it is the woodpeckers’ love of fat balls and nut feeders in gardens which have boosted winter survival. In my younger days, there were no fat balls hung in gardens and no visiting woodpeckers, which had to work for a living, searching the woods to find enough food to survive the winters rather than joining the list of species eating ‘feeder food’. Since the 1970s, the population of great spots has gone up by 300 per cent or more, and the species even started to colonise Ireland in 2008.

The rapidly increasing population of great spotted woodpeckers has also increased predation on the nestlings of hole-nesting birds. The woodpeckers bash their way into nest boxes or nesting holes to extract young tits to carry off to feed their own offspring, while they also predate much rarer and declining species such as 82lesser spotted woodpeckers and willow tits. They are a bold and aggressive species but do themselves get predated by martens in the north. The young are safer if the nest hole is firm and not easily attacked, and the nest cavity deep and beyond the reach of the marten’s front paws.

When I hear of these raids, such as the one on three tit boxes in next-door’s garden, I think of myself as a nest raider when I was young. I must have been about ten years old when, with my pals, I climbed a big elm to a green woodpecker’s nest. I was eager to take an egg for my collection, in the days before that was illegal. I went home and, without my mum knowing, took a long-handled silver spoon. I tied it to a stick and, with the spoon end bent over, tried to lift out an egg. The spoon fell off and disappeared into the cavity. I was in deep trouble; my hand was just too big to fish it out, so I had to make another trip home for a saw to enlarge the hole, retrieve the spoon and take an egg. I felt so guilty about raiding the nest and still do, but I certainly learnt how well made woodpeckers’ holes are.

It’s incredible how woodpeckers can construct these amazing nesting cavities, even in living trees; special cushioning and muscles prevent them from damaging their brains. The first bit must be hard enough, chiselling into a live tree, using the strong muscles in the neck to create an entrance hole just big enough to squeeze through – six centimetres for a green woodpecker. But then the bird has to change direction and drill down vertically inside the trunk, getting rid of the chips as it goes. It takes several weeks or even more to complete, for the internal chamber must be nearly fifty centimetres deep as well as nearly twenty centimetres in diameter. It’s a truly mammoth task for a bird.

I would love to see more holes in trees and reduce the need for artificial nest boxes, but although I’ve searched, I’ve never found a satisfactory tool that could replicate the activities of woodpeckers. 83Would it not be great if we could make one? Some American ornithologists did work out a different way of creating nest holes for one of their ...

Table of contents

• Praise
• Title Page
• Dedication
• Contents
• Introduction
• Winter
• Spring
• Summer
• Autumn
• About the Author
• Copyright