The status of pine martens Martes martes (L.) in Northern Ireland, 1850-2004

1. What they did

Pine martens were once believed to be widespread in Britain and Ireland, but loss of forest and persecution shrank their range. In Northern Ireland, little was known about where they lived, past or present. The authors set out to check the historical records rather than to map the species’ full distribution.

• Historical records. They gathered records of pine martens from published sources, government agencies, non-governmental organizations, estate records, naturalists, museums and appeals through the media. They removed duplicates (the same shot animal was often reported in several journals) and sorted the records by type (trapped or shot, sighting, scat, road kill), by time period, and by time of year.
• Scat surveys (autumn 2004). They chose 57 forests with clusters of historical records, or near them, that had tracks or roads to walk. Pine martens are known to mark their territories with scats along such routes. At each site they walked a transect of 1 to 3 kilometres and identified suspected pine marten scats in the field by their appearance and where they were placed, using published descriptions.

2. What they found

Historical records

• They found 169 records covering 1850 to 2004.
• Most 1800s records were of martens trapped, shot or snared, mostly on sporting estates (25 shot or trapped out of 31 records for 1850-1899).
• Martens killed by people declined between 1960 and 1994, but the yearly average for 1995-2004 was similar to 1850-1899.
• Sightings rose steadily from the early 1900s (47 sightings in 1995-2004), and so did road kills (none before 1960, 15 in 1995-2004).
• Of the 121 records with a date, most sightings were in late spring and early summer, though martens were seen all year.

Scat surveys

• At 20 of the 57 sites (35%), the team found 25 scats: 12 attributed to pine marten, 12 to red fox and 1 to stoat.
• Pine marten scats were found at 11 sites (Table 2): 6 of 12 sites in Fermanagh (50%), 3 of 9 in Tyrone (33%), 1 of 13 in Antrim and 1 of 14 in Down (7% each), and none in Armagh (2 sites) or Londonderry (7 sites).
• Pine marten scats were found at only 1 of 20 locations where martens had been recorded in the 1800s.
• The paper gives slightly different site totals in different places (see detailed keywords).

3. What they concluded

• Pine martens were more widespread in Northern Ireland in the 1800s than now, and their range has contracted. Game-keeping on sporting estates likely harmed the population, and the decline of those estates may explain why records fell in the late 1800s and early 1900s.
• The threats have changed: trapping by gamekeepers has declined, and road kills now appear to be one of the greatest threats. Dispersing martens would be most at risk, which could add to the effects of habitat fragmentation.
• Fermanagh and Tyrone remain strongholds. Fermanagh may be comparable in marten activity to Scotland. Overall, the scat results for Northern Ireland look similar to the rest of Ireland but low compared with Scotland. The authors caution that their sites were chosen for their historical records, so direct comparisons with random surveys may mislead.
• More records in summer may reflect martens being less active and more nocturnal in winter, but could also reflect people being out more in summer.
• Because martens may mark less in winter, the autumn timing may have reduced the number of scats found. Anecdotal evidence suggests martens still live in some places where no scats were found.
• Scat surveys alone need careful interpretation, because surveyor error is high where martens are scarce.

4. How tracking was or was not used

The survey relied on scat identification. Surveyors walked forest tracks and roads looking for scats and identified pine marten scats in the field by their appearance and placement, following published descriptions. Scats from red fox and stoat were also recognised. No genetic check of the scats was made. The authors point out that in another study (Davison et al. 2002), scats identified by experienced surveyors as pine marten were often fox where martens were rare, and in England and Wales 97% of scats thought to be pine marten were not. Historical records also included scats.

5. Tracker or observer certification

Not reported. The paper does not say who identified the scats or how experienced they were; two people are thanked for help with fieldwork. This matters because all the survey results rest on field identification of scats, which the authors themselves say can be unreliable where martens are scarce.

7. Implications for conservation (from the paper)

• Road kills may affect the long-term survival of pine martens in Northern Ireland, especially dispersing animals, and may add to the effects of habitat fragmentation on this and other mammals.
• Pine martens may not have survived in significant numbers in Counties Londonderry and Armagh.
• Future work could add genetic identification of scats or hair-snagging devices, which would be especially useful where there is anecdotal evidence of martens but few or no scats are found.