Can chicks smell their parents? No evidence of olfactory parent recognition in a shorebird

In many taxa, young can recognise their parents using olfactory cues. Yet this possibility has been overlooked in birds, because they were long assumed to have a poor sense of smell. While evidence is growing that birds use odours to communicate, olfactory parent recognition has only been documented in two altricial bird species. Whether chicks of precocial species use olfaction to recognise parents, which is currently unknown. Parent recognition is particularly important in precocial species, as chicks leave the nest shortly after hatching, and may lose contact with their parents and encounter other conspecific adults. We conducted Y-maze trials in the wild to test if chicks of a precocial shorebird, the white-fronted plover (Anarhynchus marginatus), can recognise parents via olfaction. We tested first if chicks show a preference for the odour (preen oil) of an unfamiliar adult over a control (no odour), and second if chicks show a preference for the odour of a parent over that of an unfamiliar adult. Plover chicks spent as much time with the odour of an unfamiliar adult as with the control, and as much time with the odour of a parent as with that of an unfamiliar adult. Therefore, we found no evidence that chicks react to the preen oil odour of a conspecific adult, nor that they can discriminate a parent using preen oil odours. It may be that chicks of this species can discriminate parental and foreign odours but that our experiment failed to detect it, that they rely on other (e.g. auditory) cues, or that they do not need to discriminate between parents and foreign conspecific adults.