The Chimney Swifts made a stealthy return in 1997.  When we removed the old nests from the Twin Towers on March 28^th, there were already fresh swift droppings on the floor in both.  At 7:00 PM, 4 swifts were seen circling silently through the canyon below their towers.  Two entered the North Tower to stay for the night.
      At 6:00 PM on March 29^th, 8 swifts circled the canyon in their more typical noisy fashion.  They investigated the Castle by repeatedly entering and exiting the cinderblock structure.  Three remained to roost.
      On April 6^th the North and South Towers each had a resident pair, and the Castle held a small roost of 10 birds.  By the 3^rd week of April nest construction was underway in the Twin Towers.  On May 1^st the Castle roost had grown to 47 swifts.  The experimental Prism and garden mini-tower were both occupied by May 3^rd.
      On June 1^st, a survey of all 5 structures on the station revealed a nest with eggs or young in each: South Tower - 4 young; North Tower - 6 eggs; Castle - 5 eggs; Prism - 5 eggs; Garden - 4 eggs.
      The South Tower family was captured for study on June 16^th.  All 5 of the adults were already banded. One of the 4 eggs failed to hatch, but the 3 nestlings were banded.  They fledged by June 29^th.
      The North Tower family was captured on June 26^th.  The adults in this tower were also already banded.
      The North Tower pair raised their young without the help of additional birds.  Although they hatched 5 of their 6 eggs, only 2 fledged.  Their first casualty died when it fell from the nest.  The second loss became ill and died shortly after being recovered from hanging on the underside of the nest.  The following day another nestling was found dead on the floor.  The remaining 2 flourished and fledged on July 10^th.
      The Castle family continued to be accompanied by 2 - 4 dozen swifts.  In spite of the "crowd", they hatched all 5 of their eggs.  On June 29 we opened the door to band the nestlings.  We discovered that one had died shortly after hatching (it was mummified and had become an integral part of the nest).  Another was found dead on the floor just below the nest.  The 3 survivors were fat and healthy.  They complained loudly at being handled and banded.  They all fledged by mid July.
      Because of its relatively remote location, the Garden Tower was not monitored daily.  However, enough trips were made down the hillside to know that swifts moved in by May 3^rd and laid 4 eggs by June 2^nd.  All 4 babies fledged in early July.  The nest in this tower is inaccessible, so none of the inhabitants were banded.  Modifications were made to this small tower (11" x 11" x 8') following the nest failure in the previous season.  A sun shade on the top of the south edge apparently provided the eggs with the necessary protection from direct sunlight.
      A similar modification on the Prism Tower was unsuccessful.  For a second season, the eggs failed to hatch.  Although the nest was protected from direct sunlight, the interior temperature of this single-walled structure may have still been too high.
      For the third consecutive year, the South Tower produced a second brood.  Before the first brood fledged, a new clutch of eggs was begun.  Four eggs were laid, but only one hatched and ultimately fledged.  The single nestling was extremely well fed by the extended family.  On more than one occasion an adult with a full throat of food was unable to rouse the plump, slumbering baby and had to swallow its catch.  On July 29^th the South Tower family was captured for a second time.  It was confirmed that the same swifts were the parents of both broods.  This time there were 7 swifts - not counting the slug…uh…nestling.
      Not to be outdone, the North Tower parents also produced a second brood.  By July 16^th, 4 new eggs were laid and all had hatched by August 4^th.  On August 14^th, the youngest was found hanging below the nest.  The nestling was weak and very pale (presumably anemic).  Chimney Swift Bugs (Cimex nyctalis) were found in and around the nest.  All nestlings were removed from the tower, specimens of the bugs were collected and the corner crevices of the tower were dusted with 5% Sevin.  The three older nestlings were then returned to the nest.  The youngest expired shortly after being placed in an incubator.
      On August 16^th, the North Tower family was captured and it was confirmed that both broods were from the same parents.  By September 4^th, 2 of the surviving young had fledged - leaving the third behind.  By September 7^th, the third bird had still not fledged and was often observed roosting near the bottom of the tower.  It was captured and examined.  It was observed that each of the primary flight feathers was either deformed or underdeveloped. 
      The Castle flock reached a high number of 76 on August 29^th, but diminished over the next 3 weeks.  By August 21^st the Castle was empty. As the Castle flock diminished and the South Tower family dispersed, the North Tower roost began to swell:  9/2 - 18 swifts; 9/12 - 40 swifts; 9/20 - 90 swifts; 10/1 - 137 swifts.  The North Tower reached a high of 204 Chimney Swifts on October 8^th.  The numbers began to diminish over the next few days.  We decided to capture the flock on the morning of October 12^th.  At that time there were 158 swifts in the North Tower consisting of 118 unbanded birds, 26 wild banded birds, 13 hand-reared birds and 2 escapes. On the night of October 12^th, 2 swifts returned to the North Tower and 5 others roosted in the Castle.  This is the first time we have ever had birds return after a fall banding session.  The last Chimney Swifts of the season were sited on October 14^th.  In 1997 Chimney Swifts were known to be on the station for 202 days.