Fernando Alvarez

Territoriality as a mating strategy in red deer

The mating behaviour of red deer stags, Cervus elaphus, has been extensively described as harem defence. However, it appears that territoriality may be chosen as a mating strategy when certain conditions are met. In a study area in southwestern Spain, early on in the rut, about 58% of adult males established territories in preferred areas, defended the territory against other males even in the absence of females, and courted females only within territorial boundaries. The mean territory size was about 2.3 ha. The later a male settled on his territory during the rut the fewer the females he was able to keep. The preferred areas where males established territories were also extensively used by females even before the start of the rut. The number of females per ha before the onset of the rut was positively correlated with the cumulative number of hinds that each male kept later on. Hence the reproductive success of males was largely influenced by the location of their territory. Such intensive use by females of a highly productive area for feeding and daily passage in an otherwise low-resource environment appears to promote the defence of territories located in the richest area. This paper provides the first evidence for territorial defence of mates in red deer and may contribute to the understanding of the dynamic nature of mating behaviour in ungulates. Reproductive strategies in male ungulates are mainly designed to maximize their access to recep- tive females. Gosling (1986), in a review of repro- ductive strategies of different antelope species, showed that males can adopt a variety of strategies including following a group of females over their foraging range or staying in one part of the females

Experimental brood parasitism of the magpie (Pica pica)

Egg and chick features were tested on natural magpie (Pica pica) nests. The stimuli best accepted were those of greater size and weight and of a white background and black specks. Stimuli with a shape different from oval and of low weight were the most readily expelled. Relative quantity of eggs in the nests had no strong influence on the expelling response. Chicks of house sparrows, spotless starlings, jackdaws and swallows were readily aceepted and reared by the magpies. Amongst some chicks of other species introduced, a ‘parasitic’ form of behaviour appeardwhich led them to eliminate competitors in the nests.

Behaviour of the red howler monkey (Alouatta seniculus) in the Llanos of Venezuela

The behaviour of the red howler monkey (Alouatta seniculus) in the Llanos of Venezuela was studied from May 1975 to May 1976. The average size of the social groups was 6.3±2.1 individuals. The groups were heterosexual, comprising individuals of all ages, with an average of 40% adult females, 26% adult males, 16% juveniles and 18% infants. The daily rhythm of activity for the performance of locomotion, feeding, snoozing and sleeping was ascertained for dry and rainy seasons. The density of the population in the whole area of study was 0.25 individuals per hectare of woodland, although a density of as high as 0.54 individuals per hectare was reached in some places. The use of space was established by means of locations, howls, fecal piles and scent-marking. Howlers discriminated very much in their performance of various activities in the vertical strata of trees, their use being apparently controlled mainly by the howlers quadrupedal locomotion and by the necessity for protection against predators.

COPULATIONS AND MATE GUARDING OF THE SPOONBILL (PLATALEA LEUCORODIA)

Copulatory behaviour and mate guarding of spoonbills (Platalea leucorodia) nesting at Donana National Park (SW Spain) were studied during two breeding seasons. Pair copulations were most frequent during the prelaying phase of the female, with a peak on the day before the first egg was laid. Most of the paired males (60%, N = 25) and females (76%, N = 25) were involved in extra-pair copulation attempts (EPCA) and, overall, 19 per cent of the copulation attempts recorded were EPCAs, the targets being primarily paired females. A hypothesis about the optimization of the use of sperm production by paired males is proposed: males give most of their copulatory attention to their mates during the prelaying phase, the latters uterovaginal sperm storage glands being in this way filled, and, once this is achieved, males turn their attention towards other females in prelaying phase. Devaluation of the sperm of competitors by means of high copulation frequency, optimization of the seasonal pattern of pair copulations, and intense mate guarding were the primary tactics employed by males in defence of their paternity. Considered that copulations are not completed without collaboration on the part of the female, their permissiveness towards EPCAs during the fertile period suggests advantages to females. Among the hypotheses on benefits of extra-pair copulations to female spoonbills, genetic quality of the offspring may be improved by this behaviour, and females may also benefit from the effects of intense nest vigilance by their mates.

Periodic changes in the bare skin areas ofTheropithecus gelada

Daily examination of five adult female gelada baboons (Theropithecus gelada) exhibiting menstruation discharges showed noncyclic changes in the coloration of the bare areas of skin in throat, chest, and pubic areas. The intensity of red color in these areas were, on the other hand, markedly affected by the social context (bouts of threats or fights generally heighten the intensity of red) and by sickness or injury (generally lessening color intensity).The features showing most marked cyclic variations were color and degree of swellings of the cutaneous vesicles present around the chest and ventral patches, the intensity of both increasing in the middle of the menstrual cycle and descending as menstruation approaches, to gain intensity again a few days after cessation of the discharges. Of these two features vesicle color appears to be more sensitive to the hormonal changes underlying the variations.

Social hierarchy under different criteria in groups of squirrel monkeys,Saimiri sciureus

Under different criteria the individual members of groups of squirrel monkeys show different social capacities. The ranking of the subjects was much the same for Restraining and Genital display. The hierarchies for Approaching and Following fitted well with each other, showing few similarities with the above two. Location of individual ranks for Withdrawing tended to be the opposite to that of Approaching and Following.Restraining and Genital display showed quasi-linear hierarchies, with males on top and females at the bottom of them. For Approaching, Following, Withdrawing, and Genital inspection the results varied from quasi-linear structure to circular or even unisexual arrangement. As a rule the animals behaved towards partners close in rank to themselves.Several individual roles could be isolated: An alpha male role, directing Restraining and Genital display to all other partners more frequently than any of them towards him, basing his ability more in adequate distribution of total performance among social partners than in high total frequency; an omega male role under the same criteria, whose function would be to connect with the hierarchy of females and a scapegoat role, a very passive female receiving all kinds of attention from most subjects.

The Use of the Rump Patch in the Fallow Deer (D. Dama)

The rump patch of the Fallow Deer shows different visual patterns according to the activities performed by the animals. While in calm conditions the black tail sways over the white anal field; if in alarm, the tail hangs still, dividing the white field into two parts ; in higher stress the tail tends to be raised to a horizontal position, leaving the white anal field unbroken and outlined by the two lateral black stripes; if danger is impeding the tail gets erect, showing the white underside, now seen as an extension of the white anal field, or may even go up and down, the white brush of the tail appearing and disappearing On the basis of our results on the use of the rump patch and on the frequency of defecation (high in conditions of stress) and considering that the posture of the tail during defecation is one of the most frequently observed in alarm, we hypothesize that when defecation turned to function as a communicative signal of danger, a new selective force came into play, increasing the amplitude of the movements and originating the visual pattern of the rump patch that makes them more evident.

The frontal shield of the moorhen: sex differences and relationship with body condition

Moorhens Gallinula chloropus have a conspicuous frontal shield, which is used in competitor assessment, and whose size and colour is testosteronedependent in both sexes. During 2 months in winter we examined sex-related differences in size and colour of the red or red-orange shield and the yellow-tipped bill of free-living adult moorhens, as well as their relationship with indices of body condition (body size, tarsi fluctuating asymmetry, fat index, serum lutein carotenoid concentration, and a number of blood parameters). Shield area was greater in males and more red in females. In females, area and colouration intensity of the shield were positively correlated, respectively, to body size and concentration of circulating lutein. In males, area and intensity of red colouration of the shield were positively correlated, respectively, to albumin/globulin ratio and body size, while shield colour saturation was negatively related to the leukocyte index. Our results suggest that shield area and colour of male and female moorhens may provide cues to their opponents for assessment of body size and health status, and therefore of their competitive ability.

The features of distraction behaviour and their relationship with physical condition in Rufous Bush Chats

Parent Rufus Bush Chats Cercotrichas galactotes perform of distraction display, approaching and flying away from potential predators near their nests while vocalizing and displaying their conspicuously coloured tail. The response of breeding pairs attending their first brood during the mid and final nestling stages was registered to stimuli of danger near their nests over two seasons. The first stimulus was a human observer standing by the nest and then following the parent in an experiment of distraction (first and last distances and direction of flights were recorded), the second stimuli were a Little Owl and a Corn Bunting mounts (latency and rate of tail-up were measured). For the most part, males and females did not differ in their responses. Breeding pairs were matched in first distance. Chats showed higher latency towards the control and higher tailup rate towards the owl model. The males rate of tail-up was proportional to the size of the defended brood, and males of smaller body size showed longer last distance. The relationship of the distraction behaviour with condition (body weight / keel length, haematocrit and leukocyte index) was investigated under stepwise multiple linear regression. In males higher haematocrit values were related to higher rates of tail-up display. Higher deposits of fat in the interclavicular depression were related in males to higher tail-up rates, and in females to closer first distance, and to higher number of flights away from the defended nest during the distraction experiment. In conclusion, distraction behaviour appear to depend on short- and long-term condition.

The structure of social behaviour inTheropithecus gelada

Through the use of principal components analysis of the correlation matrix between excentricity quotients of intra- and inter-individual transitions between pairs of the 22 most frequent behaviour elements of male and female gelada baboons observed in captivity, the total variance could be described in terms of a low number of causal factors. In intra-individual sequences the five factors requested of the analysis explain 74 per cent of the total variance. The following intra-individual groupings were found: (I) “autostimulation”, (II) “intensive social” versus “groom”, (III) “male sexual”, (IV) “attack” versus “sexual presentation”, and (V) “greeting” versus “threat”. In inter-individual transitions, the five factors explain 68 per cent of the variance. The following communicative sets were found: (1) “female-sexual releasing”, (2) “greeting and approaching releasing” versus “groom releasing”, (3) “austostimulation releasing” versus “male-sexual releasing”, (4) “fight releasing”, and (5) “conflict”. Mimetic induction of same acts or acts within one particular intra-individual set was frequent.