Howard L. Cogswell, Mills College, Oakland, Calif. Russel H. Pray, 662 Santa Rosa Ave., Berkeley, Calif. William K. Kirsher, .571 Fulton Ave., Sacramento, Calif. Lillian Henningson, 124 Cambridge Way, Piedmont, Calif. Address contributions for the N~VS to William K. Kirsher, F~itor-- .571 Fulton Avenue Sacramento 2.5, California PAGE EIGHTEEN THOUSAND AND FOUR CLIFF SWALLOWS by William K. Kirsher. 1 MIST NETS LEGALIZED IN CALIFORNIA. • . 4 MIST NET SUPPLIERS . • . • . • . 6 GULL BANDING IN THE KI~~TH by Carl Richardson • 7 NEVlS FROM TIIEBANDERS. 9 CHAPTER NOTES. • • • . • . • . • 10 EIGHTEEN THOUSAND AND FOUR CLIFF SWALLOWS b:{William K. Kirsher In the flat agricultural lands around Sacramento, California where in prlml- tive times Cliff swallows (petrochelidon p;trrhonota) must have been hard put to find nesting sites, today there are man-made structures that admirably fill the bird's needs for sheltered, elevated purchases for their mud nests. The species now populates the valley abundantly. Colonies are often found in culverts and under small bridges, some no higher than a man's head. In these, by working at night when all the birds are at the nest, practically the whole colony can be trapped by simultaneously closing both openings of the structure with large fish nets. Most of the m,allows flush at the first disturbance, fluttering to the nets where they are easily captured by hand. There are always a few reluctant ones that have to be flushed by shining a bright light (which the bander wears on his forehead) into the nest as he claps his hands and makes hissing sounds and other noises. The characteristic reaction of these birds is to shake their heads in obvious irritation, and, after several false starts, plunge from the nest. (cf. Stoner, Dayton, liStudies on the Bank Swallovr," Roosevelt Wild Life Annals, 4(2):127-233, 1936.) As they are captured the birds-are placed in gathering cages to await banding after which tiley are released into the night. They do not return until daylight. Using this technique 18,004 Cliff srrallows have been banded at 69 different colonies since 1949 by Wilbur H. Mayhew, Paul H. Steele, and William K. Kirsher joined from time to time by other banders whose assistance is gratefully acknowl- edged. Of these birds 17,393 were banded within a radius of thirty miles of Sacramento; the other 611 resulted from a sortie into Nevada. To this time there have been no recoveries from a distance. In any study of this kind the effects of disturbance must be considered, and, of course, most of these birds were grossly disturbed. There was one group of 192 birds, however, that was banded with the least possible disturbance. These were captured in the middle of the day, held just long enough to be banded, and then released. The return pattern of these birds, which offers a sort of control, is not different from that of those that were captured at night and re- leased into the darkness. To test the attachment the swallows have for their home colony, one group of 39 birds was carried forty miles away and released at the site of another active colony. Subsequent trapping of this second colony did not yield a single bird of thQse released. Most of them were recaptured later at the home site in a pattern little different from that of their undisplaced fellows. In other experiments: birds returned from Berkeley, 95 miles away; from the Farallon Islands, 22 miles at sea and a total distance of 115 miles; and at least three of nine birds returned over the Sierras from Nevada, surmounting an elevation barrier of no less than 7,200 feet in a distance of 70 miles. Cliff ~rallows do have a strong and abiding attachment for their nesting site. Possible detrimental effects on the eggs and young of the four to six hour absence of the parents was considered early in the work. At different times and at different colonies some fifty nests were numbered and their contents noted (with the aid of a specially designed periscope) at the time of banding and on subsequent visits at intervals that would reveal the nesting success. There was no evidence of damage due to banding activities. Summer nights in the Sacramento valley are warm, the mud nests are well insulated, and their retort ESTIMATED % NUMBER OF RETURNS 1st RETURNS 2nd RETURNS 3rd RETURNS 4th RETURNS 5th YEAR OF COLONY BIRDS YEAR AFTER YEAR AFTER YEAR AFTER YEAR AFTER YEAR AFTER CAPTUREIl BANDED BANDING BANDING BANDING BANDING ,BANDING 1951 20% 192 ADULTS 1952 95% 845 94 1953 95% 519 436 63 1954 95% 819 240 254 29 1955 60 - 70% 522 265 83 76 9 1956 95% 707 274 190 76 57 3 1952 95% 369 cJlIYENALS 1953 95% 354 54 1954 95% - 79 41 1955 60 - 70% 71 - 10 8 * 1956 95% 180 15 - 10 * 6 * * The third colony, furnishing 245 juvenals of 1952 sample and 185 juvenals of 1953 sample. was not worked in 1955 or 1956. 52 % or 2078 IJirus 27% or 1856IJirtis /5 % of 7/1 birds FOURTH YEAR 7% or 845 lJirds FIFTH YEAR 2% of /92 birds VAGRANCY PATTERN OF FIRST YEAR ADULT RETURNS /9 % or 7fJ4 birus SECOND YEAR //% or 369 lJirds THIRD YEAR 6 % of' 169 IJlrds FOURTH YEAR 5 % of' 124 birds shape prevents heat loss by convection. In every colony worked an abundant crop of young came off successfully, and the colonies continue to prosper after having been worked, in some cases twice each season, since 1951. Cliff ~{allows begin to arrive in the spring at least as early as February 25. They do not come as a complete group, but rather, the colonJT builds up over a period of two months or more. At one colony, where the nests remain from year to year, six swallows were captured February 26. Two weeks later 140 birds were taken, and on May 13, 330 - probably the full complement - were present. Most of the returning birds come to the same location at which they were banded, some even to the same nest among the hundreds of other nests of almost facsimile likeness. Where colonies are close together, however, there is some interchange. The lower right illustration represents the distribution of 373 first year returns of adults banded at one colony (circled dot) among fourteen colonies within a radius of 10 miles. All but 36 were recaptured at the home colony, and of these vagrants none were found more than four miles away. One second year return from this group was captured 9 miles away (top center circle). A compar- able number of birds from other near~r colonies appeared at the main colony considered here. The distribution of juvenal returns banded at the same colony was similar except that one was captured 23 miles to the southeast. There is also vagrancy during the breeding season, a subject considered by Dr. Mayhew in a paper presented at the 1953 AOU meeting. The return data for adults, presented in the table, were all gathered at two colonies situated in small culverts about a half mile apart. One, a double culvert~ has a popUlation each year of from 700 to 800 birds; the other, a single, averages about a fourth this number. Birds from the two culverts have a common foraging area, and there is a rather high interchange of populations involving about a fifth of the colonies. These colonies were selected to furnish return data because they have been worked longer and more thoroughly than any others. The first year, 1951, only part of the colonies (192 birds) was banded. In 1955 an accident with the nets penritted the escape of possibly 30 percent or more of the birds at one colony, and consequently data from this year are not used in constructing the graphs as they would only unrealistically reduce the return figures. The omission of these figures explains the irregular progression of sample size in the graphs. Efficiency of capture in the other four years is estimated at better than 95 percent. Juvenals are banded only when, as fully fledged and flying birds, they voluntarily leave the nest, and since only a small proportion of the young reach this stage at anyone time the sample is small. The nu~ber of juvenals banded at the two colonies described above has been augmented by a substantial number from a third colony. The juvenal returns are notable in that first, either they had already formed a destination urge toward their natal site, or perhaps they had migrated, wintered and returned in the company of the adults. And, second, of these juvenals that have returned to nest for the first time an average of 57 percent make it a second year, a higher percentage than is the case (about 47 percent) when the entire complement of a colony is banded including all ages. Other birds often share the shelter of the bridges with the ~rallows. Dur- ing the breeding season, Black phoebes and Barn ~rallows are frequently found in situations that permit them to be somewhat isolated from the busy Cliff swallows even under the same bridges. English sparrows sometimes take over swallow nests, but this is not common among Sacramento valley colonies. A dozen or more Red- shafted flickers have been captured while they were using bridge beams and supports for night roosts. Once (in the daytime) a Screech owl was found sitting in the mud cup of an unfinished ~rallow nest as though incubating eggs, but the height of the nests and the deep water below prevented investigation.