Winter Blackcap survey: Over winter 2016/2017 Blackcaps were recorded at 30 sites in the Cambridge NatHistCam study area. Overwintering of this warbler, which is mainly a summer visitor, is an urban phenomenon, encouraged by garden feeding and warmer urban temperatures. Ringing studies indicate these birds originate from southern Germany/Austria; the majority of this population join the UK birds and migrate south to north Africa to spend the winter but a small population migrate north-west to overwinter in the UK.
Breeding Rook survey: A count in March 2017 found 108 apparently active nests (AAN) at six rookeries in the study area and 111 AAN at the same six rookeries in March 2018. In 1959-60 there were 62 rookeries with 1158 AAN in our study area. The three largest rookeries in 2017/2018 were in the same locations as 1959-60; each with more or less the same number of AAN.
Mistle Thrush survey: Mistle Thrushes are a principal vector of mistletoe, the hemi-parasitic plant abundant in trees in parts of west Cambridge. They nest in March and begin singing in November of the previous year to establish breeding territories. Thirteen singing males were recorded; all were in the north and west of the city where mistletoe is most clearly seen.
Tawny Owls: A partial survey of Tawny Owls from the call of young birds disbursing from nest sites found four sites in the west of our study area and one in the east.