It is very helpful that starlings' beaks are colour coded at this time of year and even more fun that the girls are pink and the boys are blue. The pink on the bird above is not so obvious but the bird below is definitely male, even on a distant shot on a frosty morning.
I have perhaps half a dozen starling nests in the garden each year, all in holes in trees. They have to put up with multiple attacks from magpies, crows and kestrels but seem to thrive. As soon as the young are fledged they all disappear and are then infrequent visitors until the following spring.
Starlings have been in decline for many years and are on the red list of birds of conservation concern. These data are from the BTO Garden Birdwatch.
The fall in starling numbers has been across all habitats over 50 years, as shown by more BTO data.