The study was conducted from 1997–2001 in the city of Słupsk. Observations of individually marked birds were conducted from blinds located at city-centre sites where Feral Pigeons breed. The pigeons bred throughout the year, with peak broods in spring and summer. Different pairs timed their breeding such that the beginning of the season (from October to September of the next calendar year) overlapped the dates of completion (from April to December). 10% of pairs had already begun breeding in the autumn, while 86% did so between January and May. The remaining pairs (young ones, in particular) started breeding even later, mainly because of the lack of suitable nesting sites. The breeding period most often ended between August and October (75% of pairs), when the pigeons began their moult. 91% of the young birds joined the breeding population in their second calendar year of life. The remaining young birds had their first broods in the first or third calendar year of life. Pairs of young birds started nesting 2–3 months later than adult birds. The average length of a pair's breeding season was 183 days.