Cliff swallows appeared at a Chileno Valley ranch this week, six weeks later than owner Sally Gale remembers them ever having shown up as part of their annual migration. In a normal year, she told the Light this week, they “arrive at the ranch on March 15. An advance guard comes ahead, and then they all seem to arrive at once. There are hundreds of them, and we look forward to their arrival as one of the signs of spring.” The birds, recognized by their pointed wings, red-brown throats and white forehead patch, each year refurbish the nests they have built in the eaves of an old barn, using mud plucked from creeks. In the evenings they zoom through the air in intricate patterns, catching mosquitoes and other insects.