Abstract:
Incidental to his outdoor activities such as farming, fern-picking, and
horse logging, Darrel Faxon made 17.4 years of detailed observations at
Thornton Creek during 1973-1990. He determined bird presence, not bird
abundance, and made about 99,800 records, where a record is one bird species
found during one day.
Depending upon the calendar month, Faxon averaged 19-24 observation
days/month, 13-34 bird species/day, and 34-66 species/month. He noted an
average of 101 species each year.
Faxon found 12 species only during casual observations prior to 1973
and 179 species in 1973-1990. He detected 47 waterbird species, so most
birds he noted were terrestrial. 30% of waterbird species and 20% of
terrestrial species were recorded in only one year, and just 16% of the
waterbird species were seen in 16-18 years. However, Faxon noted the
majority (50.4%) of terrestrial species in 16 or more years.
For each species, daily relative frequencies of occurrence for each
month and average monthly relative frequencies of occurrence for the
1973-1981 and 1982-1990 periods are given. Further, arrival and departure
dates are listed for each species for each year, if appropriate.
Faxon's records indicate that many migratory terrestrial species are
often not present in the 10 days following their arrival or prior to their
departure. Thus, determining arrival or departure dates may be very
dependent upon daily observation effort. For example, if there are
inadequate daily observations, then the actual arrival date may be missed,
and it may be several days or a week before the species may re-appear. This
inconsistency of presence after their "arrival" results in many species not
being found on their "average" arrival date.
Although Faxon did not record a spring migration wave, he usually noted
a major movement of passerines during August-September. In fall, his
records also indicate that some raptors appeared to be migrating through.
In addition to his bird observations, Faxon recorded daily
precipitation from 1975-1990, and monthly totals are given.
