|Electronic Supplementary Material
Relation of group size and daily activity patterns on Southern lapwings (Vanellus chilensis)
Pietro K. Maruyama, Amanda F. Cunha, Everton Tizo-Pedorso, Kleber Del-Claro
Material and Methods
Components of behavioural ethogram
The major part of the behavioural acts used in the registering process had already been described by Costa (1994a, b, c, 2002). The alert behaviour was, characterized by the birds standing up, with its head raised, scanning the environment. For this, it seems that alert behaviour can not be concomitant with foraging, since these birds forage on the ground, with their heads down.
The feeding behaviour was considered when we could see the birds lowering the head and touching the ground with their bill, a characteristic movement of catching something. Sometimes these birds did not effectively contacted the ground after lowering their head, but since we could not suggest the purpose of these “lowering the head” behaviour, it was included in the foraging category. It is interesting to register that big items, like earthworms, demanded more effort from the birds while feeding, with manipulation by head movements and by their feet. Nevertheless food manipulations that demanded more effort were rare, and most events of food manipulation had similar duration, including the rapid movements of ‘lowering the head’ behaviour. Southern lapwings exhibited two defensive behaviours besides escape, crouched in camouflage and distraction displays (sensu Costa 1994c, 2002). Crouching as a defence behaviour (crouched in camouflage) is not essentially different from resting crouched, and it was characterized only when the presence of a potential threat was seen, as well as in the case of distraction displays. Other behaviour associated to defence was vocalization (Costa 1994c, 2002). Birds’ vocalizations were characterized depending on the situation in which they happened. Thus, alert vocalization was emitted during alert behaviour, and vocalization in response was emitted as a response to another individual’s vocalization, that many times was out of our view. Neutral vocalization was characterized when it was not possible to identify any of the situations above. Vocalization in alert was included in the vigilance behaviour analysis, since it is exhibited by birds on vigilance.
Maintenance included most behavioural acts cited by Cotgrave & Clayton (1994). Standing still and resting crouched behaviours were considered sleeping behaviours. Considering that birds generally sleep in these positions and these two behaviours were commonly performed for longer periods (more than two minutes) (Amlaner & Ball 1983), they probably involve sleeping events. Behavioural acts that apparently did not correspond to none of the other behavioural categories were grouped in miscellaneous. The total frequency of these behaviours was relatively low (ca. 4.5%), what may minimize the possible bias to the analysis of behaviours frequency in relation to group size.
We performed 100 hours of qualitative and quantitative observations of Vanellus chilensis behavior. In total, we registered 32 distinct behavioral acts, divided into nine categories. Behavioral categories and acts are summarized in Table S1.
Table S1. Behavioural repertories of Southern lapwings in the Parque do Sabiá, Uberlândia-MG, Brazil. Were quantified 19636 behavioural repetitions in 75 hours of observations.
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