The selection of indicators species is based on the pan-European classification of breeding bird indicator species and, more precisely, its class Common farmland birds in Europe. In addition to the species included in this class two species that are particularly common in Finland - Eurasian Curlew and Common Rosefinch - have been added to the Finnish indicator. Of these species, the former is too rare on a European scale to be included in a common indicator. The European population of the latter has a strong emphasis on Finland and Russia. In the Finnish ecological classification of birds the class farmland birds has traditionally included also other species such as Common Pheasant, Stock Dove, Wood Pigeon, Common swift, House Martin, Pied Wagtail, Fieldfare, Magpie, Jackdaw, Hooded Crow, Common Sparrow and Greenfinch. Now these species have been included in the indicator on Urban birds.

The monitoring of breeding birds is based on regular counts carried out by both volunteers and professionals. The most important monitoring methods is the line transect count. Since 2006 transect counts have been made on a standard route network, which covers the whole country at 25 km intervals. There are altogether 538 standard routes each equalling 6 km in lenght. Annually 20–25% of the routes are surveyed. Before 2006 the routes could be freely determined by the counters. In addition to routes, some monitoring data are also collected by mean of point counts and comprehensive local censuses.

A transect count involves walking along a predetermined route and making notes of all observed bird individuals. The count is made during the most intesive singing period in early summer. The counter stops every 50 metres at minimum to listen to singing individuals. All observed birds are marked down for either a 50 metres wide main strip or a supporting strip outside of this. Birds observed along the route are interpreted as couples according to a standard practice: both a single singing male and a flock of up to five individuals of the two early breeding Crossbills species are interpreted as one couple, for example