Chimney Swifts arrived clandestinely in 2000.  They avoided our eyes and ears to the sky only revealing themselves by their overnight droppings in the Castle.  Our routine mid-morning inspection showed evidence of roosting birds from the evening of March 21.  Two individuals were observed entering the tower on the following evening.  By April 15, the nightly registry rose to 64 swifts.  Additional birds continued to join the flock with the total reaching 97 on May 5.  Nest construction was well underway by May 7 with overnight roosting activity beginning to diminish.  By May 14, three eggs had been laid and only two birds were in residence.  Numerous birds attempted to roost but insistent chippering and defensive wing clapping from the mated pair dissuaded them.
    The first of the five eggs laid hatched on June 3.   Midmorning on June 5, 3 human juveniles new to the neighborhood climbed the property fence and attempted to open the Castle door.  Six to nine year old boys are not very subtle and were quickly discovered.  They were given an intense education about Chimney Swifts and then escorted back to their own yard.  The swifts recovered from the disturbance and four nestlings successfully fledged.
    A roosting flock began to congregate on June 20 when 16 birds entered at dusk.  By July 4, 52 swifts were chippering inside the Castle.  At nightfall, a steady barrage of fireworks began to build to a crescendo within the neighborhood.  The tower birds flushed in seconds and circled above the canyon.  Only 12 individuals were observed returning to the structure in the darkening sky.
    The fall roosting flock returned by mid July and reached a total high of 63 individuals.  The mean temperature during evening observations from August through mid September was 87°F  with an unbelievable high of 108°F  on September 5 at 7:30 P.M.   The last three swifts were observed entering the Castle on September 20 leaving the last accumulation of scat and molted feathers as evidence of their summer habitation.

    A scientific modification was made on all of the swift towers on the station prior to the birds return. Each structure was fitted with an indoor-outdoor thermometer that would enable a comparison in interior temperature variations of the structures.  This addition required installing a probe inside the nesting chambers.  Care was taken to position the probes as discreetly as possible.  However, the swifts returning to the North Tower took great exception to the change in their home.  The pair noisily discussed their displeasure while also wing clapping and giving the apparatus the "evil-eye".   One bird actually grasped the probe with its foot.  The pair gradually accepted the change and claimed the tower on April 17.  That evening, one bird began a vocalization that we refer to as "singing".  The sound is a quiet, monotonous vocalization of  "me-me-me-me….".  Until this instance, we had only documented "singing" in juvenile birds. 
    The pair produced five eggs.  Four eggs hatched, but only two birds survived to fledge on July 5.
    A roosting flock began to assemble in mid August.  Infrared lights allowed after dark observations within the tower.  We discovered that swifts remain very restless and continue to fly within the tower well past sunset. 
    Beginning in September, the fourteen to nineteen nightly visitors increased to 37.  The birds then began roosting higher in the tower above camera view.  Following a cold frontal passage on September 24, the high number of 72 swifts began to disperse.  Subsequent cold fronts in the following weeks blew the birds south with the last single individual lingering until the morning of October 22.

     
    One bird took up residence in the South Tower on March 24.  Surprisingly, the mate did not arrive until ten days later.  The pair was the same two birds that nested in this tower in 1999.  One was a South Tower nestling in 1999 while the other was a North Tower parent in 1998.
    The first nest stick was glued to the west wall on April 25 and the first egg was laid on May 6.  Their six eggs hatched, however, two hatchlings expired.  One was found dead on the tower floor, the other was dead in the nest.  Half of its eggshell was stuck on the top of its head, which probably made it impossible for the nestling to feed.  The four remaining nestlings were banded and fledged on July 4.
    The parents continued to enter the tower during the daylight hours following the fledging of their young.  They were often observed on or below the nest and occasionally entered the tower with   a stick in their bill.  Unfortunately, their attempts to repair the nest damaged by their offspring failed and a second brood was not produced.
    Between seven and eleven birds returned to roost each evening until October 16 when the last bird was observed.

    A pair of swifts returned to the North Pool Tower on April 16.  Five eggs were laid but 1 rolled over the edge.  The nest holding the remaining four nestlings began to sag following successive June thunderstorms but did not fall from the tower wall.  By July 12 no birds were in residence.  An inspection of the tower revealed a mummified twelve-day-old nestling in the misshapen nest.
    The South Pool Tower remained unoccupied throughout the season.

   
    Modifications were again made to the Prism Tower.  In addition to the probe for the thermometer, an access door was cut, rigid insulation and white vinyl siding and trim were installed over the existing siding. 
    A pair of swifts was in residence on April 16 and was occasionally joined by two or three additional birds in the evening.  The entire clutch of five eggs hatched and the young were banded.  The family returned to the tower until mid August at which time they probably joined the growing roost in the North Tower.

    This 11" x 11" x 8' tower was modified for the New Year.  An access door was cut; rigid insulation and hardboard siding were installed as well as a top and a thermometer. 
    Chimney Swifts inspected the structure both inside and outside but did not occupy this tower.

NEXT PAGE