Level of local human disturbance and feeding state determines escape behaviour in Eurasian Oystercatchers

Recommendations on How to Use Flight Initiation Distance Data in Birds

Birds and other wildlife are negatively affected by many anthropogenic activities, including human recreational activities, which are often not considered in area planning. Here, I present factors affecting the flight initiation distance (FID)-the distance to an approaching human at which birds flee-for 1075 different flocks of waterbirds. The FID varied greatly between groups of birds and species. For some bird groups and species, the FID was longer in rural areas than in urban areas and increased with flock size and with disturbance from canoeing. In addition to the differences in FID between species and groups of species, there are two important conclusions from this study: (1) a graphical relationship between the proportion of birds that flee at different distances from an approaching person gives more information than mean or median FID values and should be used by nature managers, and (2) the FID should be investigated in each area before mitigating actions or new constructions are decided, considering all the factors affecting it. A global database with a mixture of FID values from a huge number of areas is valuable for some purposes but can be misleading for individuals in a specific area.

Does a roosting flock of migratory birds also echelon in high winds?

The organized aerial manoeuvres of birds in “V” and “J” flock echelons have always captivated onlookers and several of these aspects are still a matter of ongoing research. However, we could not find any published evidence or report on echeloning in a roosting flock of birds in high wind conditions. Here, we provide first evidence of an echelon in a roosting flock of the Eurasian oystercatcher (Haematopus ostralegus ostralegus) at the onset of Storm Malik in Scotland on the morning of the 29th of January 2022, under ~ 11 ms−1 winds. This observation opens-up several new research questions on if, how, and why birds position themselves in a flock while roosting in high winds.