A study spearheaded by the Wildlife Conservation Society and the University
of Minnesota has shown that the world's largest owl — and one of the rarest — is
also a key indicator of the health of some of the last great primary forests of
Russia's Far East.

The study found that the rare and spectacular Blakiston's Fish Owl relies on old-growth forests
along streams for both breeding and to support healthy populations of their
favourite prey: salmon. The large trees provide breeding cavities for the
enormous bird, which has a two-metre (6ft) wingspan. And when these dead,
massive trees topple into adjacent streams, they disrupt water flow, forcing the
gushing river around, over, and under these new obstacles. The result is stream
channel complexity: a combination of deep, slow-moving backwaters and shallow,
fast-moving channels that provide important micro-habitats critical to salmon in
different developmental stages.

 The study appears in the October issue of the journal Oryx and is
currently available online as a
PDF. The authors, including Jonathan Slaght of the Wildlife
Conservation Society, R. J. Gutiérrez of the University of Minnesota, and Sergei
Surmach of the Institute of Biology and Soils (Russian Academy of Sciences),
studied the foraging and nesting characteristics of Blakiston's Fish Owl in
Primorye, Russia, where they looked at nesting habitat over 20,213 square
kilometres (7,804 square miles). They found that large old trees and riparian
old-growth forest were the primary distinguishing characteristics of both nest
and foraging sites.

The authors say that management and conservation of old-growth forests is
essential for sustaining this species because they are central to the owls'
nesting and foraging behaviour. Moreover, conservation of Primorye's forests and
rivers sustains habitat for many other species, including eight salmon and trout
species that spawn there; some of the 12 other owl species found in Primorye;
and mammals such as the endangered Amur (or Siberian) Tiger, Asiatic Black Bear, and Wild Boar. Listed as Endangered by IUCN, Blakiston's Fish Owl is restricted to riparian areas in Russia, China, Japan and possibly North Korea.

"Blakiston's Fish Owl is a clear indicator of the health of the forests,
rivers, and salmon populations," said lead author Jonathan Slaght. "Retention of
habitat for fish owls will also maintain habitat for many other species
associated with riparian old-growth forests in the Russian Far East."

There are fears that Capercaillie populations in the southernmost part of their range are no longer viable despite intensive efforts to save them. A cluster of small populations in the Trossachs and Argyll have steadily declined over recent decades. The last of these populations, centred on some of the Loch Lomond islands, has now dwindled to the point where there are only a few birds left. The nearest strong population is now in the Cairngorms National Park — well beyond the distance that Capercaillie will travel to search for territory or a mate. This leaves any remaining birds on the islands isolated, with no realistic prospect of being joined by individuals from elsewhere. While some birds may still be spotted on the islands, they are very few in number and little or no breeding is taking place. Long-running efforts by Loch Lomond & The Trossachs National Park Authority, Scottish Natural Heritage (SNH), RSPB Scotland and local landowners have not been able to halt this decline.

The strongest Capercaillie populations are in the Cairngorms National Park. The last national survey in 2009–2010 estimated that 80% of the UK population was in the Park, the vast majority in Strathspey. Numbers there currently appear stable. Capercaillie populations in Scotland and across Europe are under pressure from a range of factors. Recently these have included a run of wet summers, which have seriously affected chick survival. However other factors include predation, loss or fragmentation of habitat, collisions with deer fences, and human disturbance. The decline in the southern Scottish populations is likely to have been due to a combination of these factors.

The organisations working to protect Capercaillie in Scotland are advocating a pragmatic approach to targeting resources where they will be most effective in maintaining viable populations. Alan McDonnell of SNH said: "The Capercaillie is a highly valued part of Scotland's nature, culture and history and we are committed to ensuring its long-term survival. A lot of people and organisations have worked for many years to help the population of Capercaillie on the Loch Lomond islands, but we need to face the facts about this increasingly isolated group of birds. As things stand, we need a pragmatic approach to Capercaillie conservation and our resources are focused on preserving the core populations in the north of the country."

Alan Bell, natural heritage manager for Loch Lomond & The Trossachs National Park Authority, added: "Despite all our shared efforts the simple fact is that no new birds are moving into the area to breed with the resident birds. Although individual birds were spotted in 2012, we have seen no signs of breeding activity in the last two years. The islands are rich places for nature and the efforts to protect the important wildlife there will of course continue."

Anne McCall, RSPB Scotland regional director, said: "The loss of the iconic Capercaillie from the Loch Lomond islands is a real disappointment. Combined efforts to reverse declining population trends have not succeeded and this situation highlights the pressing need to take fast, targeted action wherever possible. As such it is increasingly important that resources are found to support work elsewhere for our remaining Capercaillie populations if they are not to suffer the same fate."

Dennis Robertson, the SNP MSP who is the species champion for Capercaillie in the Scottish Parliament, commented: "I am naturally disappointed at the stark prospect for the Capercaillie in this part of Scotland and I am sure many of my colleagues will share my frustration. However we have to face the facts that Capercaillie populations have shown an unfortunate, but steady, decline, here, and in some other places. What we must do now is redouble our efforts to nurture and protect this iconic bird in areas where it is doing better and I am committed to that task."

In striking contrast to last week's report on the relation between feeding and the reproductive success of Great Spotted Woodpeckers, new research1 claims that feeding wild birds during the winter could harm the success of any chicks born in the following spring. Scientists carried out the study on nine sites across Cornwall, where over three years they supplemented the Blue Tit population's winter food with nothing, balls of fat, or fat enriched with vitamin E. Nest boxes at the sites were then checked the following spring to assess how the number of eggs, and the size and success of any chicks, related to the amount and type of extra food provided.

The study, published in Scientific Reports, found that when extra food was given Blue Tits produced smaller chicks, which had a lower chance of survival than the chicks that didn't receive any additional food. Dr Jon Blount of the University of Exeter, who led the research team, explained that, "Although the precise reasons why fed populations subsequently have reduced reproductive success are unclear, it would be valuable to assess whether birds would benefit from being fed all year round rather than only in winter".

Supplementing birds' sparse winter diet with commercially available food is common in the UK and USA, with more than half a million tonnes of commercial bird feed sold each year in the two countries. Vitamin E was used in the study for one test group as it is often found in bird food such as seeds and nuts. Previous studies have shown that giving wild birds additional food can have an almost immediate benefit to their survival, and can enhance future breeding success. Dr Kate Plummer of the British Trust for Ornithology, who is first author of the research, says that a possible reason for the findings is that extra food helps birds who would not otherwise have survived to breed. The poor condition of these birds means they can only raise a small number of chicks.

Whether providing food is detrimental or beneficial to wild bird populations, it is clear that more research is needed to better understand its effects. Blount concluded that "More research is needed to determine exactly what level of additional food provisioning, and at what times of year, would truly benefit wild bird populations."

The paper's abstract is as follows:

"Supplementation of food to wild birds occurs on an enormous scale worldwide, and is often cited as an exemplar of beneficial human–wildlife interaction. Recently it has been speculated that winter feeding could have negative consequences for future reproduction, for example by enabling low-quality individuals to recruit into breeding populations. However, evidence that winter feeding has deleterious impacts on reproductive success is lacking. Here, in a landscape-scale study of blue tits (Cyanistes caeruleus) across multiple years, we show that winter food supplementation reduced breeding performance the following spring. Compared to unfed populations, winter-fed birds produced offspring that weighed less, were smaller, and had lower survival. This impairment was observed in parents that had received fat only, or in combination with vitamin E, suggesting some generality in the mechanism by which supplementary feeding affected reproduction. Our results highlight the potential for deleterious population-level consequences of winter food supplementation on wild birds."

Researchers have found that providing extra food in early spring leads to earlier egg laying and increased productivity in Great Spotted Woodpeckers. Birdwatchers have been amazed by the big increase in the numbers for Great Spotted Woodpeckers over the last 15 or so years. In a paper in the latest issue of Bird Stud, the journal of the British Trust for Ornithology, authors Ken and Linda Smith provide a potential explanation for the woodpeckers' success.

In a wood in Hertfordshire, Great Spotted Woodpeckers were provided with suet blocks at 13 feeding stations distributed over half of a 100-ha study wood from early February until late April 2011, with the other half of the wood left unfed. In the spring of 2011 breeding attempts in the 'fed' zone were earlier, by an average of four or five days and birds there produced almost twice as many fledged youngsters as those in the unfed zone, even though the supplementary feeding stopped before the main period of chick rearing.

BTO members Ken and Linda Smith had been studying the woodland for the previous five years and found no differences between the zones in any of the previous years when no extra food was provided. The availability of caterpillars, the natural food for the breeding woodpeckers, was measured by using 'frass' traps to collect their droppings. 2011 was a very warm spring and the abundance of natural prey peaked very early. This meant that none of the woodpeckers' breeding attempts were well synchronized with the emergence of the caterpillars. However, the small advancement in first egg date meant the supplemented birds were better synchronized than the birds that did not have access to suet blocks. Birds in the fed areas raised an average of 4.2 chicks per pair, compared to 2.1 chicks per pair in the unfed areas. Ken Smith said, "Having studied these birds for best part of 30 years, I was amazed at the difference extra food made in 2011. A few days' shift in egg-laying date allowed them to be so much more productive."

The response of Great Spotted Woodpeckers to supplementary feeding suggests that they may be limited in their ability to shift their breeding period in response to the earlier boom in caterpillar numbers. This has important implications for the response of the birds to warm springs, which are expected to be more frequent under future climate change. By using feeders, Great Spotted Woodpeckers breeding in woodlands close to gardens may well be able to avoid problems caused by the changing timing of the spring season. By producing a big brood of youngsters, even in early springs, garden-feeding parents may be helping to fuel the current population increase.