The importance of crossroads in faecal marking behaviour of the wolves (Canis lupus)

1. What they did

Wolves mark their territories with urine and with secretions from glands, and scats probably play a part too. A scat left at a busy, prominent spot is more likely to be found by other wolves. People who know wolves say crossroads are good places to find their tracks, but how wolves use crossroads for scat marking had not been well documented.

The researchers studied a wolf population in Montes do Invernadeiro Natural Park, northwest Spain, from May 1998 to March 2000. Over 14 surveys of 2 to 3 days each, they searched 837.2 km of unsurfaced roads, asphalt roads and firebreaks for wolf scats, and mapped each one on a 1 km grid.

They compared how many scats lay:

• Inside crossroads: the area where two or more roads meet.
• On the periphery: the stretch of road up to 30 m from the centre of the crossroads.
• Along the rest of the roads.

They worked out how many scats would be expected in each zone if scats were spread at random, allowing for the extra chance that a wolf passes through a crossroads compared with any single point on a road. They also noted whether each scat lay on a conspicuous or raised object.

For each of 99 crossroads they recorded the number of roads meeting there, the kinds of road, the surface area, the altitude, the accessibility (how important the roads were as routes between areas, scored 1 to 3) and the driveability (how easily a vehicle could travel them, scored 1 to 3).

2. What they found

Where the scats were

• They found 311 scats: 67 inside crossroads, 120 on the periphery and 124 along the rest of the roads.
• Far more scats were inside crossroads and on their periphery than expected by chance. Inside crossroads there were 8.30 scats per km, compared with 1.67 on the periphery and 0.15 along the rest of the roads.
• Together, crossroads and their periphery held 60.1% of all scats. (The abstract calls this “at crossroads”.)
• The closer to the centre of a crossroads, the more scats. Even so, 57.8% of scats lay between 2 and 10 m from the centre.
• Grid squares with more crossroads held more scats.

What the scats were on

• At crossroads and their periphery, 72.1% of scats were on conspicuous or raised objects, compared with 45.6% along the rest of the roads.

Which crossroads were chosen

• Crossroads where four or more roads met held more scats on average (5.7) than those where three roads met (3.2).
• Crossroads with more scats were those with higher accessibility and driveability, and to a lesser extent those with a larger surface area. Altitude and the type of road made no difference.
• Grouping the crossroads gave three clear types: 12 with high accessibility, high driveability and many scats (6.83 on average); 24 in between (3.21 scats); and 63 with low accessibility, low driveability and very few scats (0.30).

3. What they concluded

• Wolves travelling along roads choose crossroads for their scats. Because wolves can arrive at a crossroads from several directions, a scat there is more likely to be found by other wolves. Scats on conspicuous objects add a visual signal to the scent.
• Wolves favour crossroads that link different mountains and important areas of their territory, such as the rendezvous site. Crossroads with low accessibility are hardly marked, probably because wolves rarely use those roads.
• The same crossroads were marked again and again. The authors suggest wolves are drawn to old scats and mark over them, so that piles of scats (latrines) build up.
• The most heavily marked crossroads were far apart and on mountain tops, where scent spreads better. The authors suggest this marks territory borders against intruders.

4. How tracking was or was not used

The study is a scat survey: the researchers searched roads and firebreaks for wolf scats and recorded where each lay and what it was on. The paper does not say how scats were identified as wolf scats, and no footprints or trailing were used.

5. Tracker or observer certification

Not reported. The paper does not say who found and identified the scats or how their identification was checked. Several people are thanked for help with the fieldwork and surveys.

7. Implications for conservation (from the paper)

• Because scats pile up at crossroads, crossroads give clear evidence that wolves are present. Knowing where wolves are and how many there are, which needs indirect methods, is essential for their conservation.
• Crossroads rich in scats could supply valuable material for non-invasive studies, such as DNA work and stress hormone (glucocorticoid) measurements.