Face masks in action: Birds show reduced fear responses to people wearing face masks during the COVID-19 pandemic in three Asian countries

Abstract

The 2019 zoonotic pandemic (COVID-19), has led to a massive global lockdown that provides a good opportunity to study how wildlife responds to changes in human activity. Wearing a mask after the COVID-19 outbreak was widely used to prevent the spread of the causative pathogen. It has been shown that tree sparrows (Passer montanus) at two sites in south China exhibit reduced fear responses to people with face masks after a period of heavy exposure to them, whereas European studies showed the opposite, with no changes in the behaviour of the birds towards mask wearers in either rural or urban areas. To further study this, from October 2021 to January 2022, we conducted a flight initiation distance (FID) survey in Pakistan, Bangladesh, and Xi'an, China for a variety of field bird species by comparing the FID for researchers wearing masks to that for researchers not wearing masks to assess whether wearing masks in public places caused birds to adjust their flight response. Results from the three Asian countries showed that after a period of sustained contact with people wearing masks, in both rural and urban areas, birds were significantly more adapted to them and had a shorter FID to people wearing masks. We suggest that the rapid habituation of birds to people wearing masks with a reduced fear response could have some fitness advantage, allowing them to adapt rapidly to the new environmental conditions induced by COVID-19.

Keywords: Antipredator behaviour; COVID-19 lockdown; Face mask; Flight initiation distance; Habituation.

Graphical abstract

Fig. 1

Study area of Mardan, Pakistan.

Fig. 2

Study area of Jahangirnagar University, Bangladesh.

Fig. 3

Main fixed effects on flight initiation distances of birds in three countries (a refers to mask type, b refers to habitat type, with error bars showing the standard error).

Fig. 4

Main fixed effects on flight initiation distances of birds in Pakistan (a refers to mask type, b refers to habitat type, with error bars showing the standard error).

Fig. 5

Main fixed effects on flight initiation distances of birds in Pakistan (a refers to mask type of rural area, b refers to mask type of urban area, with error bars showing the standard error).

Fig. 6

Main fixed effects on flight initiation distances of birds in Bangladesh and China (a refers to mask type of Bangladesh, b refers to mask type of Xi ‘an, China, with error bars showing the standard error).