City birds:
half an hour at a pet shop and 1 hour max for the set up can bring you over 20 different bird species in front of the window, at least in countries around Belgium.
Hang 2 bird feeders on the sides of a window, one for peanuts and one for sunflower, a nail for a fat ball under the window and drill a hole to plug a photographically pleasing tree branch in the wall. In a day or two, Blue Tit and Great Tit will start whirling around and their activity will attract other birds to the feeding station. Adding a rectangular flower pot with Calluna vulgaris left and right will attrack early bees in spring and provide some shelter for birds which prefer feeding on the ground. Chicken food will keep them returning. Most birds will stop first on the branch for a second of two.
What I've seen with this set up: Blue Tit, Great Tit, Coal Tit, Marsh Tit, Crested Tit, Robin, Long-tailed Tit, Greenfinch, Goldfinch, Siskin, Chaffinch, Brambling, Blackbird, Yellowhammer, Nuthatch, Eurasian Jay, Tree Sparrow, House Sparrow, Dunnock, Eurasian Magpie, Great Spotted Woodpecker
Warnings:
- it works in winter when food sources are scarse. Most of the birds disappear when they start nesting
- not all feeders are equally attractive to a large number of species: These designs are better:
https://www.amazon.de/Gardman-A01232-Futtersäule-Kunststoff-Ausführung/dp/B001F3BAV4/ref=pd_cp_86_1?_encoding=UTF8&psc=1&refRID=04WT3TXDVFWP6MW32XVY and
https://www.amazon.de/Hammarplast-932544-Vogelfutterhaus-Kunststoff-rund/dp/B001QB7K28/ref=pd_sim_86_7?_encoding=UTF8&psc=1&refRID=SC3Z1QNVPWD53CSWBBDB - don't give peanuts when the birds are nesting. Often they bring them to the chicks wich can't swallow them and die.
- take a window in a room you can cool down to external temperature or the temperature differential will create sharpness issues
