I can set my calendar by the arrival and departure of Bee-eaters in our area here - well, within reason anyway! I have noted their arrival and departure in the years 1990 to 2019 and only once have they either arrived or left more than 36 hours distant from the 1st April and 31st August. The anomaly was 2013 when they arrived 5 days early.
Wildly colourful they are also graceful fliers, swooping low over the fields with rapid wing-beats followed by glides catching bees and other insects in flight. The bees they take to a perch and either pinch or knock out the sting before consumption. They breed colonially in tunnels excavated anew each year in the side of streams or banks of earth. They are said to devour 250 bees each per day, but as this would entail catching and eating one on average every three minutes, I am doubtful, especially as it is documented that 10% of their time is taken up with "leisure activities", i.e. preening, dust-bathing, etc Their impact upon the number of bees in an area is inconsequential unless one's hives happen to be close to a colony.
