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Capercallie: A Review of Research Needs

4 IMPROVEMENTS IN CONSERVATION PRACTICE

4.1 Introduction

Moss & Picozzi (1994) provided the first recommendations on managing forests for capercaillie in Scotland. This publication still gives sound advice, but it needs to be better targeted to achieve an improvement in the fortunes of capercaillie. Management can address many of the current problems if correctly scaled, targeted and resourced. Importantly, beneficial effects for capercaillie could be achieved quickly through prompt action at an appropriate scale with factors such as predation, fence collisions and high deer densities. Whereas action over forest-related factors will have a delayed impact since it takes time for these to feed through into habitat improvements.

4.2 An outline management strategy

The Forestry Commission's Highland Conservancy has produced a map showing the boundaries of core and extension areas (Figure 2), based on a questionnaire sent to sporting estates, reserve wardens and Forest Enterprise rangers in 1990 and subsequent responses to the questionnaire (Catt et al., 1998). Core areas include the most important populations and habitats for capercaillie. Within core areas the Capercaillie Project Officer is currently identifying the most important sites, called key sites. Extension areas have fewer capercaillie and less prime habitat, but nevertheless provide suitable habitat (much of which could be improved) into which capercaillie could expand following an improvement in breeding success in the core areas. Some extension areas will no longer hold capercaillie, but probably would if the population started to recover. The core and extension areas have been split into four geographically distinct zones (Figure 2) and some basic woodland data provided for each zone (Table 5).

This three-tier classification allows management effort to be more effectively targeting at the most important sites for capercaillie. The salient point to remember is that if the decline in numbers cannot be reversed in key sites then capercaillie will almost certainly be lost from Scotland. Therefore, proportionally more effort should be put into the management of key sites to try and improve breeding success and reduce adult mortality than in core and extension areas. One uncertainty at present is the proportion of the core areas that will be classified as key sites.

A summary of the proposed management package is given in Table 6. This lists 15 elements, which are expanded in the next section and are largely based on existing advice (Moss & Picozzi, 1994) or on important points to come out of the review (section 2). No distinction is made between semi-natural pinewoods and plantations, although some of the elements are less applicable to the management of semi-natural pinewoods.

It is proposed that the package should be given a forest-scale trial in key sites for three years (3.2.3), then modified in the light of experience gained and implemented. While many of the more important areas for capercaillie are privately owned, it should not be forgotten that publicly owned land is also important, and a mechanism is required to encourage the participation of Forest Enterprise.

4.3 Elements of the management package

4.3.1 Fox and crow control

Foxes and crows take capercaillie eggs and chicks and both can be legally killed. The review indicates that both are involved in reducing breeding success, although in Scotland the evidence against crow is stronger than that against foxes (2.7.3). This is mainly because the impact of foxes has not yet been tested experimentally. The use and funding of predator control needs to reviewed periodically to ensure that the returns justify the cost. Importantly, management techniques that result in lower predator numbers should be encouraged (4.3.6, 4.3.12 & 4.3.15).

Effective predator control is time consuming and needs to be limited to the time of year that has greatest benefits for capercaillie. The aim should be to reduce the density of foxes and crows during the period when eggs and chicks are vulnerable, and when predator numbers are at a seasonal low point. Trapping and shooting would need to start at least by early March, so that predator numbers are declining by the time that egg laying commences at the end of April. Control measures would continue until the chicks are large enough to fend for themselves (end of August). The main methods of control would be Larsen traps for crows (Reynolds, 1990; Anon, 1994) and night shooting with spotlights, snaring and killing at dens for foxes (Anon, 1994). Foxes are more difficult to control than crows. Snaring appears to be one of the most effective methods, but can kill non-target species, including capercaillie. Guidelines on improved snaring techniques are already being prepared under the auspices of the Game Conservancy Trust and Capercaillie Project Officer. Simple monitoring methods need to be developed to gauge the effectiveness of these control measures.

4.3.2 New fences

Fence collisions are an important cause of mortality in adults (and black grouse too), and appear to be implicated in lower survival rates. Therefore, there should be less dependence on fencing (also see 4.3.3-5) and more reliance on limiting deer number by culling (4.3.6). This approach is likely to have other benefits linked to improvements in ground vegetation, such as better feeding for adult capercaillie, better brood habitats, reduced predation and more tree regeneration. Importantly, such beneficial effects are likely to operate over a much larger scale than by fencing vulnerable areas.

No new fencing should be allowed in key sites other than in exceptional circumstances, and in core areas only with full agreement of consulted bodies and capercaillie experts (Table 6). There are a number of alternatives to conventional fencing currently being examined, which will be reviewed as outlined in section 3.2.5. However, any use of non-conventional fencing will have to be agreed with FC in consultation with SNH and DCS.

4.3.3 Inventory of existing fences

An inventory of deer fences in key sites is recommended (see 3.2.2.).

4.3.4 Removal of internal fences

The inventory of fences in key sites will rank fences according to their perceived danger to capercaillie. A plan should then be prepared listing fences with the highest rankings, and landowners consulted about their removal. In other core and extension areas, collate existing information on hazardous fences, and plan the removal of as many as possible. WIGs may be available for fence removal, but landowners cannot be compelled to remove them outside designated (some) sites.

4.3.5 Mark remaining internal fences

Justification will be required to retain fences with a high ranking in key sites. These will need to be marked with two strips of orange netting. In other core and extension areas, mark collision "hotspots" with two strips of orange netting on fences that are to be retained.

4.3.6 Deer density targets

Manage deer by culling rather than by fencing whenever possible. Follow recommendation in FAS Guidance Note (Forestry Commission, Under revision) when culling is the main means of control, but in key areas reduce densities to < 5 deer km². Deer are shot thought the year (open seasons; hinds 21 October - 15 February, does 21 October - 31 March, stags 1 July - 20 October, bucks 1 April - 20 October). Under heavy culling regimes, grallochs from shot deer provide a readily available food source for crows and foxes (Griffith, 1992), particularly during winter when natural foods may otherwise limit numbers of scavengers to a lower level. In key sites, consider the removal of grallochs to a slurry pit, as practised by the RSPB at Abernethy, as this may well lead to fewer scavengers (I.P. Bainbridge pers. comm.).

4.3.7 Dogs

Uncontrolled dogs are particularly disturbing to capercaillie from around the time of lekking until chicks are flying well (April - August inclusive). Signs banning dogs during this period (and explaining why) should be placed at entrances to key sites. In other core areas and extension areas dog access may be either prohibited or allowed with the use of a lead, depending on the sensitivity of capercaillie to disturbance.

4.3.8 Human disturbance to leks

Human activity, including forestry operations and birdwatchers, can cause disturbance to leks, and to brood habitats when chicks are small. Visitors should be encouraged to adhere to the Birdwatchers Code of Conduct (Table 7 and RSPB, 1999). In addition, public access agreements that fail to take account of capercaillie should not be supported. Access arrangements should be agreed at an early stage of a WGS application stage, and routes altered when required. The RSPB are providing viewing facilities at a lek near Loch Garten, started in spring 2000, which should be used to divert birdwatcher's attention from vulnerable sites. No forestry operations should be undertaken within the vicinity of leks during March-May inclusive.

4.3.9 Annual lek counts

All leks in key areas should be located and numbers of displaying males counted annually during the last 10 days of April. Care should be taken in locating leks as they can move short distances, particularly in response to disturbance. This will give a crude index of the success of the package. Leks outwith key areas should be counted whenever possible and in a consistent manner annually. Lek counts provide one method for assessing temporal trends in numbers of cocks. Sex ratios in populations can vary from year to year, and so numbers of cocks counted at leks are unlikely to reflect trends in the number of hens (Helle et al., 1999).

4.3.10 Improving brood habitat

A general impression is that there are large areas of under thinned plantations that could be made more attractive for capercaillie, particularly for broods. These are mainly plantations of Scots pine with blaeberry present. Thinning should aim to improve these as potential brood habitats. Blaeberry is encouraged when canopy cover is greater than 40%, tree height over 10 m, and tree density > 1500 ha^-1. Once tree densities fall below 500 ha^-1 and canopy cover is less than 30 %, heather is encouraged rather than blaeberry (Moss & Picozzi, 1994). Thinning intensity should be variable, even to the extent of creating small clearings to encourage tree regeneration. Ideally, thinned areas should be linked to other suitable brood habitat, including wet areas (2.5.2), which can often be extended by drain blocking. Wet areas with cotton grass or lush vegetation are particularly important, and even more so when adjacent to blaeberry patches.

4.3.11 Stand management methods

In appropriate stands (particularly Scots pine) encourage the use of alternative management systems to clear cutting (Hart, 1995). Multi-structured stands, with a proportion of older trees with large crowns and younger trees, can combine the winter requirements of adults with those of broods, while at the same time providing more cover and shelter than found in even-aged stands. Try to link important areas of non-native woodland to the more natural parts of the forest. Avoid clearing small windblown patches, particularly where the trees are still alive, as these provide both feeding opportunities in winter and cover.

4.3.12 Clear-cut size

Clear cuts should be as small as possible, especially within key areas. Clear cuts with grassy vegetation can sustain high densities of field voles, which in turn support higher fox densities (Lambin et al., 2000; O'Mahony et al., 1999). Therefore, a move away from clear cutting and towards continuous cover crops should be encouraged, particularly on sites where grass is likely to form a high proportion of the ground vegetation after clear cutting. Larger clear cuts should be located on sites where ericaceous vegetation is likely to develop. Avoid clear cutting in and around lek sites.

4.3.13 Retention of old conifer crops

The retention of old conifers is crucial to the management of capercaillie. First, the area of such stands within a forest has a direct bearing on the carrying capacity of the forest for capercaillie. Old conifers should be encouraged as a component of continuous cover stands. Second, old conifers with large crowns are particularity important during winter (2.3) when they provide most of the food for capercaillie. Scots pine is the most significant species, but other conifer species are also important, in particular larch and Douglas fir, but also Sitka spruce and silver firs. Retentions are more valuable for capercaillie when located near to lek centres.

4.3.14 Species choice for new woodlands

Use native species whenever possible. Scot pine is the most important conifer, but juniper is valuable for cover. Aspen can be browsed by capercaillie in spring and autumn and should be more widely encouraged on appropriate sites, but it is also heavily browsed by deer and so successful establishment will depend on maintaining low deer densities. The most useful non-native species is larch, followed by Douglas fir.

4.3.15 Link new woodlands to a forest habitat network

Preference should be given to new woodland proposals that link with existing areas of woodland (Ratcliffe et al., 1998; Peterken et al., 1995). This will help reverse some of the detrimental effects of forest fragmentation. Large forests are likely to hold fewer crows and foxes than landscapes comprising forest and farmland mosaics. Small holdings within forests can help sustain larger numbers of crows and foxes if they provide suitable foods, such as surplus food for domestic stock, dead animals and cereal crops.

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