Abstract: During contests animals typically exchange information about fighting ability. Among feral horses these signals involve olfactory or acoustical elements and each type can effectively terminate contests before physical contact becomes necessary. Dung transplant experiments show that for stallions, irrespective of rank, olfactory signals such as dung sniffing encode information about familiarity suggesting that such signals can be used as signatures. As such they can provide indirect information about fighting ability as long as opponents associate identity with past performance. Play-back experiments, however, show that vocalizations, such as squeals, directly provide information about status regardless of stallion familiarity. Sonographs reveal that squeals of dominants are longer than those of subordinates and that only those of dominants have at their onset high-frequency components.

Abstract: Evidence is accumulating that cognitive abilities are shaped by the specific ecological conditions to which animals are exposed. Long-distance migratory birds may provide a striking example of this. Field observations have shown that, at least in some species, a substantial proportion of individuals return to the same breeding, wintering, and stopover sites in successive years. This observation suggests that migrants have evolved special cognitive abilities that enable them to accomplish these feats. Here we show that memory of a particular feeding site persisted for at least 12 months in a long-distance migrant, whereas a closely related nonmigrant could remember such a site for only 2 weeks. Thus, it seems that the migratory lifestyle has influenced the learning and memorizing capacities of migratory birds. These results build a bridge between field observations suggesting special memorization feats of migratory birds and previous neuroanatomical results from the same two species indicating an increase in relative hippocampal size from the first to the second year of life in the migrant but not in the nonmigrant.

Abstract: Animal flight behaviour in response to aircraft could have a profound influence
on the accuracy and precision of aerial estimates of population size but is rarely
investigated. Using independent observers on the ground and in the air we
recorded the presence and behaviour of 17 groups, including 136 individually
marked horses, during a helicopter count in New Zealand’s Kaimanawa
Mountains. We also compared the helicopter count with ground-based
estimates using mark-resight and line-transect methods in areas ranging from
20.5 to 176 km2. Helicopter counts were from 16% smaller to 54% larger than
ground-based estimates. The helicopter induced a flight response in all horse
groups monitored. During flight, horse groups traveled from 0.1 up to 2.75 km
before leaving the ground observer’s view and temporarily changed in size and
composition. A tenth of the horses were not counted and a quarter counted
twice. A further 23 (17%) may have been counted twice but only two of the
three observers’ records concurred. Thus, the helicopter count over-estimated
the marked sub-population by at least 15% and possibly by up to 32%. The net
over-estimate of the marked sub-population corresponded to the 17% and 13%
difference between helicopter counts and ground-based estimates in the central
study area and for the largest area sampled, respectively. Feral horse flight
behaviour should be considered when designing methods for population
monitoring using aircraft. We identify the characteristics of the helicopter
count that motivated horse flight behaviour. We compared our own recent
estimate of population growth from measures of fecundity and mortality (λ =
1.096 with an earlier-published one (λ = 1.182, where r = 0.167) that had been
derived by interpolating between the available history of single counts. Our
model of population growth, standardised aerial counts, and historical estimates
of annual reproduction suggest that the historical sequence of counts since
1979 probably over-estimated growth because count techniques improved and
greater effort was expended in successive counts. We used line-transect, markresight
and dung density sampling methods for population monitoring and
discuss their advantages and limitations over helicopter counts.

Abstract: Background
Feral horses (Equus caballus) can cause significant environmental damage and losses to
rural industries. Although considered pests, feral horses are also a resource, providing
products such as pet meat for the domestic market and meat for human consumption
for the export market. Control methods include trapping, mustering exclusion fencing,
ground shooting and shooting from helicopters.
Feral horses are mustered by helicopter, motorbike or on horseback, sometimes with the
assistance of coacher horses. Once mustered into yards, net traps or fenced paddocks, the
horses are usually sold to abattoirs for slaughter which can offset the costs of capture and
handling. Less commonly, they are sold as riding horses or relocated to reserves or horse
sanctuaries. Where there is no market for them or where removal may be too costly or
impractical e.g. in conservation areas or remote areas without access to transportation,
horses are sometimes destroyed by shooting in the yards.
This standard operating procedure (SOP) is a guide only; it does not replace or
override the legislation that applies in the relevant State or Territory jurisdiction.
The SOP should only be used subject to the applicable legal requirements (including
OH&S) operating in the relevant jurisdiction.