In the French study sites from 2009 to 2014, meadow passerines were surveyed twice every week by a walking observer, from mid- April to the end of the haymaking. During each visit, individual birds, song displays and agonistic behaviors were plotted on a 1:8 000 map. When the hatching period started, every individual Whinchat, Corn Bunting and Yellow Wagtail (the most common passerine species) was systematically checked with binoculars to verify whether it carried prey to feed its chicks. Successive visits were made every 2–3 days, but each survey was intensive (>4 h), ensuring a reliable detection rate. Passerines carrying prey were usually observed within known territories. Otherwise, prey carrying was assigned to the nearest territory after checking that corresponding adults were absent in this territory. The hatching rate was defined as the proportion of territories in which at least one prey carrying episode was observed, indicating that at least one egg hatched per territory. In the Russian study sites from 2010 to 2013, meadow birds and prey carrying by passerines were mapped only once a week between May 1 and July 30 but each survey was more intensive (notably with 2 observers instead of 1). The observation of prey carrying in such conditions cannot strictly reflect hatching success since nests may hatch and fail between visits. This indicator (that we will refer to as “hatching rate” or “hatching success”) may nevertheless enable us to describe the influence of increasing TD and possible density dependent effects on nesting success shortly after hatch.