RACING PIGEONS – IMPACT OF RAPTOR PREDATION

4.2 RESULTS
4.2.1 Reported Losses
Reported losses of racing pigeons to sparrowhawks were allocated to one of three
categories dependent on the level of evidence collected which gave support to the loss
being in fact due to sparrowhawk predation. Only five losses were followed by
recovery of a carcass and its return to CSL. Examination of these carcasses
confirmed diagnostic features consistent with sparrowhawk predation (substantiated
losses). A further 10 incidents were reported where a carcass was recovered
following a loss. In most of these cases the reason given for not passing on the
carcass was that the loft-owner ‘forgot’. In a further 63 incidents of reported losses to
all causes, 14 losses were ‘believed’ by the loft owner to have been due to
sparrowhawks but no substantiating evidence was provided (possible losses). Also,
among these 63 incidents, seven losses were believed to be due to raptors other than
sparrowhawks - six peregrine and one goshawk. Data on categories of losses at all
lofts are summarised in Table 4.1 and illustrated in Figure 4.1. However, the
possibility cannot be excluded that some of the ‘possible’ losses were not caused by
sparrowhawks, or that some losses attributed to other causes were in fact the result of
sparrowhawk attack.
Considering all substantiated, probable and possible losses the number of reported
losses from the loft area attributed to sparrowhawks was 29, representing an average
of 0.91 birds per loft (Table 4.2). There was variation in attributed sparrowhawk
losses between the four principal regions of Scotland, ranging from 0.2 birds per loft
in Ayrshire to 1.4 birds per loft in Dunbartonshire/Stirling. Considering only the 15
lofts which reported losses, the mean loss per loft was 1.9 racing pigeons (range 1 to 4
birds per loft – all categories).
At the level of the individual loft, reported losses (all three categories pooled) ranged
from zero to four birds (Figure 4.2). Nearly half of the sampled lofts (47%, n=15)
reported losses to sparrowhawks. These losses were regarded as substantiated at 5
lofts (16% of all lofts), probable at a further 6 lofts and possible at 4 more. Seven
lofts recorded losses of single birds whilst eight reported multiple losses of two to
four birds. Considering only substantiated losses, single losses only were reported
from each of the five relevant lofts. For substantiated plus probable losses, reported
losses ranged from one to three for the 11 relevant lofts.
Losses to sparrowhawks were considered in relation to the total reported losses to all
causes from the loft area (Table 4.3). For individual lofts, substantiated sparrowhawk
losses (5 lofts) represented a median of 20% of total losses to all causes from the loft
area: range 7% (1/14) to 100% (1/1); substantiated plus probable losses (10 lofts):
median of 14%, range 4% (1/28) to 100% (1/1); substantiated plus probable plus
possible losses (15 lofts): median of 20%, range 2% (2/91) to 100% (1/1). Two lofts
(Fife 8 and Stirling 5) each reported a single probable loss to a sparrowhawk during
the 12 month study period but reported no losses from the loft area to other causes
during the associated six month racing season.
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