Islais Creek Pacific Chorus Frog Rescue Project page 1 of 3
Overview: Jim McKissock, founder of Earthcare, has been hired by the San Francisco PUC to save the Pacific Chorus frog population from habitat loss at Muewekma Olhone Sanctuary as a result of the Islais Creek Booster Pump Station Force Main project and the Islais Creek Bridge project.
1. Establish artificial breeding sites
a. Several breeding tanks to be sited at various strategic locations to encourage breeding west of Illinois Street
b. Capture adult frogs from construction area and hold and care for in terrariums until breeding season in Dec thru Feb
to be released at breeding sites. Frogs begin to call at the beginning of breeding season, which varies greatly from year to year
c. Enhance established water features at east end of Muewekma Sanctuary by increasing vegetation, improved structural cover and providing food (crickets). Captured adult frogs may be introduced into enhanced area during the breeding season.
2. Collect eggs from breeding sites
a. During the breeding season, survey the entire area for
additional possible breeding sites. No adequate natural sites have been located at this time, however several areas containing large rain puddles nearby may attract breeding frogs where eggs may be collected.
b. Due to general loss of habitat in the surrounding area, this
entire population is at risk and eggs should be gathered wherever found.
3. Raise tadpoles for reintroduction into selected areas
a. Identify areas which will provide needed cover, carrying capacity and breeding potential to establish permanent breeding populations.
b. Permanente breeding areas may require artificial
enhancements, i.e. access to municipal water supply for creation of breeding ponds and to sustain vegetation.
c. Froglets may require additional first food such as flightless fruit flies, which can be raised or purchased.
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4. Establish Frog Watch program to monitor locations and strengths
of the frog populations. Large areas may be surveyed by using simple listening techniques. It is possible to determine the strength of a breeding population at a given location by the number or intensity of calls. Residents and businesses in the area to be surveyed may be notified through posted notices or direct canvassing
Calling is rated generally as 0 through 3. Level 0 is no calling and may mean a population at a known breeding location has died out. Level 1 is one or more frogs calling but with gaps between calls. This often occurs at the beginning of the season and strengthens as time goes on. Level 2 is several to many individuals calling, with calls over lapping. Breeding may occur at level 2 in small populations. Level 3 is many individuals and a loud sustained chorus, so many calls it is difficult to pick out a particular individual. Breeding is almost certainly occurring or soon will.
Only male Chorus Frogs call, females have no voice pouch under their chins. The lack or presence of a voice pouch (loose skin) under the chin is the easiest way to determine the sex of individuals.
Calling is related to the temperature and usually doesnÕt occur when temperatures are below 55 degrees. Warmer nights after sundown are the best time to listen.
Information gathered in the field is called or e-mailed into a central location and later verified and located on a map which provides future surveyors a benchmark from which they can determine the present strength at a given location.
I have been asked to supply a short term plan for the rescue of this
population , however the frogs continued survival depends on efforts that must extend out into the future. This population will lose the only known local habitat and established breeding pools as a result of the two construction projects mentioned above.
On Oct. 31 we were able to catch one male frog and attempted to relocate it across from the pools at Pier 80 on the west side of Illinois St. in David EricksonÕs garden with a breeding pool we recently set up. Unfortunately we found this frog dead, run over in an attempt to find his way home. Initially we were going to simply release frogs captured in the construction area into vegetated areas on the west side of Illinois St. However this is a clear indication that frogs soon to be caught in the construction area will attempt to return to that area, resulting in the deaths of most if not all the frogs during
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construction activities. It is often the case that frogs will attempt to return in the direction from which they were removed. In order to keep frogs out of
harms way, the frogs caught in the construction area will be held in large terrariums and fed crickets until breeding season. Adults may be relocated near artificial breeding pools and at newly created habitats. The artificial breeding pools will be set up along the west side of Illinois St. and may still prove valuable as Pacific Chorus Frogs often range over one hundred yards from their breeding sites and undiscovered individuals may be hiding west of Illinois St.
It is essential that permanent adequate breeding locations be found or created, to replace those that will be lost. The entire purpose of collecting eggs and rearing froglets depends on achieving this long term goal.
Long term stewardship and restoration may begin at the Muewekma Sanctuary as soon as work on the force main project has been completed and a proposal acceptable to the Port Authority is completed. IÕm now working on a proposal that would greatly enhance the habitat value and native plant diversity, and also create a public stewardship group or association that would interact with the Port Authority. It has been proven by the present existence of the currant frog population that at least a small breeding population can be supported at the Muewekma Sanctuary. Continued access to the currant municipal water supply is essential for purposes of establishing native plant communities and for maintaining proposed water features. This line should be protected or replaced during the street and rail construction on
Illinois St. associated with the Islais Creek Bridge Project.
I hope we can all share in the success of these efforts. IÕm sure that with the continued good will and cooperation of everyone concerned, we will be able to over come any obstacles that may lay in our path.
Remember, these little creatures have survived every thing that has been thrown at them, from the beginning of all time, accept us.
Thank You All Very Much Jim McKissock