Ease of capture in lines of Japanese quail (Coturnix japonica) subjected to contrasting selection for fear or sociability

Japanese quail (Coturnix japonica) of lines, which have been subjected to c ontrasting selection for duration of the tonic immobility (TI) reaction or social reinstatement (SR) behaviour over many generations show correspondin g differences in underlying fearfulness and sociality. As fearfulness and s ociality are particularly influential traits in domesticated species, the f inding that such traits respond to artificial selection may have important implications for poultry welfare and performance. However, it is not known if or how such selection has influenced human-animal interactions. The pres ent experiment investigated the influence of fearfulness and SR behaviour o n the ease with which birds could be caught and handled. Birds of lines sel ected for duration of the TI response or SR behaviour were reared in mixed Line groups (LTI and STI or HSR and LSR) of 491 and 346 birds, respectively , until 6 weeks of age. When the birds were 2, 4, and 6 weeks of age, they were caught one by one and their individual capture ranks noted, In the gro up of birds selected for duration of the TI response, birds selected of the Line selected for short duration of TI were caught before those selected f or long duration of the response. In the group of birds selected for SR mot ivation, birds of the high line were caught before their low lines counterp arts. Coefficients of concordance between capture ranks were significant an d capture ranks did not differ significantly across ages. These results imp ly that selection for low levels of fear or high levels of sociality produc es animals that are less disturbed by human interventions than animals sele cted for the opposite traits. The greater ease of capture of low fear line birds than high fear line birds may be explained by reduced fear of humans. The fact that the birds selected for high levels of SR behaviour are easie r to catch than birds selected for low levels of sociality is less readily explicable. One hypothesis is that HSR line chicks tend to be more strongly imprinted on each other and the human caretaker. However, SR behaviour is highly species specific in both lines, existing evidence for line differenc es in social discrimination is limited and birds of the two lines show simi lar duration of the TI response. Despite this, whatever their underlying ca usation, these results demonstrate that genetic selection can be used to re duce negative reactions to human beings and may be of value in the improvem ent of both animal welfare and productivity. (C) 2000 Elsevier Science B.V. All rights reserved.