Feeding the Macaques

One of the reasons that the Army was tasked with the management of the Barbary macaques in 1915 was that these animals would venture down to the town in search of food, and were becoming a nuisance, frequently raiding kitchens and taking fruit from gardens in close proximity to the Upper Rock. It was thought, erroneously as it turned out, that if they were fed up the Rock they would not venture into areas of human habitation. Initially, the Army was tasked with maintaining the population to within twenty-five animals and after 1955 to a minimum of thirty-four (Burton & Sawchuk 1974). Fa (1984) distinguishes four distinct periods of provisioning, distinguished by type and volume. From 1936 to 1946 only a proportion of the daily food requirement was provided, and some of this consisted of refuse from the cookhouse, resulting in widespread enteritis. The rest was obtained by the macaques through foraging. A similar volume of food was provided from 1946 to 1960, but in this case no cookhouse refuse was given. The absence of cooked and waste food during this period was responsible for the revival of the colony (Zeuner 1952; Fa 1984).

There was an increase in the size of the population between 1960 and 1967, resulting in the macaques being promoted as an important tourist attraction. This resulted in an increase in the volume of food provided. The provisioning of the second group took place at Princess Caroline’s Battery, but this was later moved to Middle Hill. The quantity of food was increased a second time in 1970 with the aim of preventing animals wandering down to town. In 1980, culling of the population, which had been carried out by the Army without publicity, ceased (Fa & Lind 1996). This resulted in an increase in the population from 33 in two groups in 1970, to 105 in 1993 and 190 in 2001.

The amount of food given throughout this period is difficult to quantify, but the actual expenditure on provisioned food found in the ‘Gibraltar Government, Revenue and Expenditure Estimates’ gives us an insight into the history of the management of the macaques. This started with £10 from 1940-50, and increased to £81 per animal per year in 1981 (Fa 1984). Roaming and foraging of the macaque groups was reduced (but not halted), possibly as a result of the increase in food supplied. Significantly, the Queen’s Gate group greatly reduced its home range, presumably as a result of this and the considerable interaction and feeding by tourists. This is in stark contrast to the Middle Hill group, which although also experiencing a reduced home range, still foraged for extra sustenance.

Figure 1. Current home ranges of the macaque groups (2004).

In his conclusions, Fa (1984) stated that there were current problems in overfeeding and overall disturbance from people visiting, and that the effect of this was proving detrimental to the breeding of the species and could present further problems in the future. Although this might be true, what in fact happened was an increase in the population coinciding with a huge increase in visitor numbers. Sights Management made considerable dietary improvements, on advice from GONHS, by providing a range of fruits and vegetables in the early morning and sunflower seeds and peanuts in the afternoon. Water was supplied daily but no vitamin or mineral supplements were provided, although the animals showed no deficiencies (Lewis 1997).

When GONHS took over the feeding, emphasis on “natural foods” and ensuring a nutritionally complete diet in accordance with the ‘Martin Plan’ (Martin 1997) was adopted. Additional nutritional advice was obtained from Dr. Jutta Küster, the biologist responsible for the captive population in Salem and later Daun in Germany. A minimum of 500g per animal per day was introduced on her recommendation. A breakdown of food provisioned during 2000 and 2001 is shown in Table 1 as an example. Recommendations on the feeding and routine management of the sites were undertaken where possible but not all sites have running water for adequate cleaning of the feeding area.

Table 1. Breakdown of food in kg /yr. for the years 2000 and 2001.

It must be stated that the amount of food given in Table 1 supplements the diet of the Barbary macaque. The macaques tend to forage frequently in search of their dietary preferences. This includes berries and wild fruit, roots and leaves and occasionally invertebrates.

Perez, C.E. & Bensusan, K. (2005) The Upper Rock Nature Reserve, A Management and Action Plan. The Gibraltar Ornithological & Natural History Society. Gibraltar.