Visual Contact with Humans and Condition in Domesticated Budgerigars

Abstract

Regular, non-aversive interaction with humans can reduce domestic and captive animals’ fear of them. This has management implications because it can sometimes beneficially affect the animals’ condition, reproduction and productivity, probably as a result of a reduction in chronic stress. We determined for domesticated budgerigars living in flocks whether regular visual contact with humans for six weeks affected body mass, condition and peripheral blood parameters that are thought to indicate chronic stress levels. Contact comprised 300–360 min of visual exposure weekly to an experimenter pacing slowly in front of the aviary; control flocks had no exposure, except briefly during husbandry. Body mass and condition and the blood parameters were measured at the start (Sampling time 1, ST1) and end (ST2) of the treatment period and again after a further six weeks in which all birds were isolated from humans (ST3). Mass, residual mass (i.e. condition) and blood haemoglobin concentration were greater at ST3 than at ST1 or ST2, the heterophil/lymphocyte ratio increased from 0.35 to 0.67 between ST1 and ST2 and haematocrit decreased from 59 to 54% during the experiment. Improved nutrition and adjustment to the new environment were possible factors influencing these temporal trends. The changes were similar in visually exposed and control birds, so regular visual contact with a human of the specific type and extent imposed had no effect on body mass, condition or the blood parameters. Possible reasons for the lack of an effect are discussed.