Dagit, Rosi

Aquatic Commons

20 NOTICIAS DE GALAP AGOS No. 47
en otro lugar. Durante la noche del 8 de diciembre,
el galápago No. 13.264 se movilizó 45 m a otro lugar.
Estas observaciones nos indican que a veces las
tortugas se mueven para consequir mejor dormitorio.
Talvez la observación más estraña ocurió en la
zona de anidación (D), los Guayabillos. Durante la
noche del 15 de noviembre de 1982, C. Márquez
acompañado por H. Serrano observó un galápago
juvenil No. 13.800 que anochió refugiado a unos 8 m
de la carpa. A las 2050 se observó el animal inquieto
yempezando a moverse. Al mirarel animal alumbrado
con una linterna, se vio al galápago pasar a 2 m frente
de la carpa, escol tado por una 1echuza, Asio f/ammeus.
El galápago amaneció en otro refugio unos 60 m de
distancia del primero.
En el caso de los animales que se desplazaron en
la garúa, concluimos que andaban buscando agua. El
motivo de los desplazamentos en diciembre cuando
no había lluvia no es tan claro. No sabemos si el
movimiento por el animal acompañado por la lechuza
fue por efecto del ave o si ésta lo montó para
aprovechar la oportunidad de cazar de una plataforma
movil. Cruz Márquez y Solanda Rea, Estación
Científica Charles Darwin, Isla Santa Cruz,
Galápagos, Ecuador.
IN SEARCH OF THE DARK-RUMPED PETREL
By: Rosi Dagit
"!t's raining in the highlands!" This remark has
come to have special significance for several students
who, over the past 3 years, have spent many very wet
days searching the area around Media Luna on Santa
Cruz for nest burrows of the Dark-rumped Petrel
(Pterodroma phaeopygia). The students carne to
Galápagos beca use they were intensely interested in
the fate of the Dark -rumped Petrel, and were willing
to put up with the cold, wet, dirty clothes and soggy
sleeping bags in order to contribute to the study of
these incredible birds. The Dark-rumped Petrel
breeding areas are limited to the highlands of four
Islands in the Archipelago, with declining populations
on Santa Cruz (Baker 1980), Santiago, and Isabela
(Harris 1970). Only on Floreana, where Felipe and
Justina Cruz have instigated an intensive protection
program, has the breeding success increased (from
32% in 1982 t075% in 1986 [Cruz and Cruz 1986]).
Although most visitors remember the Islands as
sunny, dry, blistering piles oflava rocks, the highlands
of Santa Cruz can be just the opposite. Often draped
in garúa, they call forth images of a prehistoric time,
and life, amid a tangle of dense, wet vegetation. Into
these thickets, the Dark-rumped Petrel s come at
night to dig their nests, mate, and raise their young.
As darkness descends and the stars fade away in the
encroaching clouds, the haunting calls of these birds
echo through the night. How they find their burrows
year after year remains a mystery. Why they choose
such an unlikely area is also unclear. Other members
of the Procellariiformes are al so ground nesters, but
they tend to select isolated Islands and areas along
cliffs for their breeding grounds.
The birds select nest sites in moist soils along the
banks of sinkholes, gullies, and streambeds, and they
are especially vulnerable to predation by rats and
dogs. On Santa Cruz, the close proximity of farms to
the breeding areas has led to drastic losses of eggs
and chicks to introduced animals. Since 1978, the
number of active burrows has declined at arate of
33% peryear, leadingtopredictions oftotal extinction
within 10 to 15 years (Coulter et al. 1982). A
protection program for the Media Luna area on Santa
Cruz, similar to the one on Floreana, has been planned
and begun under the guidance of Feli pe and Justina
Cruz.
This program seeks to approach the prob1em of
population decline from several directions. First,
monitoring of known nesting areas is continued.
Second, Mirador crater was set aside as an area to be
enclosed by fencing. This would serve to keep out
dogs and pigs and to complement the heavy poisoning
to control rats in a limited area. Artificial burrows
were dug in choice locations to encourage more birds
to nest there.
Third, a team, under the direction of Dr. Stephen
Kress and Dr. Richard Podolsky, began a project
designed to determine the influence of social
March 1989 NOTICIAS DE GALAP AGOS 21
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A bird in the hand...in this case a Dark-
rumped Petrel...is worth a lot of work
(photograph by R. Dagit). Un pájaro en la
mano.. .en este caso un petrel o pata
pegada... vale mucho trabajo.
stimulation on nest site selection (Kress and Podolsky
1987). By broadcasting tapes of recorded sounds of
petrel colonies, pre-breeding birds might be attracted
to sites wi thin the protected area. During the summer
of 1988, the researchers began the f1rst stage of this
experiment by broadcasting the
sounds and setting up mist nets
to capture any birds attracted
by the broadcasts. In addition
to the study are a near the caseta
at Media Luna, tapes were also
broadcast within Mirador
crater each night.
June 1988 was dry in
Galápagos, and for the first
time in 3 years our study team
had hope that we might not get
wet in the highlands. But, on 4
July when we arrived at the
caseta, the garúa set in to stay.
Dry paths quickly became
quagmires and c10thes took on
a permanently wet and
mildewed odor. The 10
students and two instructors
from International Student
Research (ISR) had offered to
help the Cruz team with the
large task of removing invading
Cinchona succiruba, an
introduced pest species, from
Mirador crater so that the en-
demic Miconia robinsoniana
would become reestablished.
In addition, we planned to
repeat our 1986-87 transects of several nest areas
near Media Luna and to help monitor the mist nets
during the all-night petrel vocalization project.
Life in the small caseta was pretty crowded, with
5 Park wardens, 5 members of the Petrel Project, and
12 people from ISR. All meals had to be cooked in
shifts and, because the heavy mist never ceased,
eaten inside. Bold "kitchen finches" competed with
hungry researchers for crumbs. "Rey, you in the
feathers, that's my breakfast!" became a constant
chorus. Our tents quickly became ponds in the
continuing rain. One particularly wet moming, a
soggy student carne to breakfast somewhat
disgruntled, complaining poetically that "Every
morning I wake up in despair, with mildew growing
in my hair!" Despite the fact that nearly every
morning meant putting on wet, dirty c1othes, our
team kept up their spirits by
singing and by attacking the
Cinchona with a vengeance.
After waiting our turn to
cook and eat breakfast, we
would hike through the Fem/
Sedge zone to Mirador
crater. Along the way we
often encountered curious
Short-eared Owls, which
would sit and with puzzled
gazes watch us pass.
The Cinchona eradi-
cation in the area was started
years ago, and it seemed for
awhile that the Park wardens
were able to keep it under
control. However, funding
cuts and a changing focus
meant that large areas were
still vulnerable to being
invaded by dense stands.
Cinchona was introduced to
Galápagos in the 1940s with
the hope of selling quinine,
which was made from its
bark. The tree quickly
became naturalized, and
spreading vegetatively as
well as by seeds, it out-
competed much of the endemic Miconia. It is not
c1ear whether the Dark-rumped Petrel populations
are directly affected by the vegetation shift, but
everyone felt the protection of Mirador in its natural
condition was important. Rence, the removal project.
In 4 backbreaking, blister-producing days, the
team pulled up well over 4,000 trees. Earlier
eradication efforts had left stumps with roots intact,
and only years later did biologists realize that these
had sprouted into large multiple shoots, capable of
covering areas of 5 m2. With only one axe but with
lots ofteamwork, we were able to successfully remove
22 NOTICIAS DE GALAP AGOS No. 47
all Cinchona trees, large and small, from the crater,
with the exception of those in the area with the
recently dug artificial burrows. The Park wardens
cheerfully assisted the students with the largest trees.
Soon the area was dotted with large piles of trees on
platforms prepared for us by the wardens. All roots
and shoots had to be placed above the ground because
new roots would appear quickly from excavated
plants touching soil. Several days later, with a great
sense of satisfaction, we stood at the rim looking
down on the destroyed plants. We hoped that the
Miconia would be able to regain its foothold.
However, when we turned tú hike back to the caseta
and saw the extensive stand s of Cinchona colonizing
the outside flank of the crater, we realized how much
work remains to be done. It will take constant
vigilance to keep the Cinchona from reinvading.
Our plant work had other benefits for the project.
In the course of crawling under the remainingMiconia
in search of small shoots, several previously
undiscovered burrows, two with birds inside, were
discovered. Each afternoon we would take a break
from pulling the Cinchona and hike transects with
either Felipe or Justina Cruz to monitor nests. The
nest burrows can be as deep as 2 m, so even when a
bird is heard inside, it can be difficult to remove it for
inspection. The preferred technique is to lie flat on
your back, stick your hand in slowly, and let the bird
bite your finger so that you can then drag it out.
Despite the fears of some students who worried about
disturbing the birds, previous experiments had shown
little effect of investigator interference on breeding
success (Bass 1980).
Even with bloody and bruised fingers, the students
carefully held the birds so that measurements of
wings, tarsus, and beaks could be taken. Each bird
was also weighed and banded, if necessary. Any
eggs found were also weighed and measured. The
students enthusiastically crawled along the banks in
search ofburrows. Jane Gray became immortalized
when she located a new nest with birds in it and
Felipe named the nest after her! As each student
assisted with the project by finding burrows or holding
the birds, their determination to do whatever was in
their power to save those birds increased visibly.
Most interesting was an adult petrel found that had
originally been banded as an adult by Michael Harris
in 1968-69 (ED22101). Because these birds don't
begin nesting until they reach 8-9 years of age, this
bird now was probably well over 20 years old! What
stories it could have told, of nests destroyed, chicks
fledged or killed by rats, and flights throughout the
Archipelago in search of food.
Equally excitingwere the results of the vocalization
experiments. Using a variety of tapes of petrel
colony sounds, a random selection was played for
half-hour intervals all through the night. Large mist
nets were unfurled to monitor the entrance of birds,
and eagerresearchers waited, hidden under a tarp, for
something to hit the nets. Data on birds heard calling
or flying by were also noted. Any birds caught in the
nets were weighed, measured, and banded if needed
before being released.
On the last night of our visit, one female petrel
flew into the net on her way out to sea after laying her
egg. Her band number documented that we had just
weighed her earlier that afternoon prior to her
depositing an egg at her nest. It was great to have
such specific information on pre- and post -egg weight,
accurate date of laying, and nest location. Further
monitoring of the nest promised to add information
about incubation time by each adult, duration of
incubation, and fledging.
On our way back the next day to the Darwin
Station, showers, and dry c1othes, one volunteer
echoed the feelings of all when he remarked that he
had never been so dirty, tired, wet, and happy in his
whole life! Having the chance to work for the
preservation of this species was definitely the highlight
of all our projects in Galápagos.
The fate ofthe Dark-rumped Petrel as a species is
by no means assured des pite all the efforts currently
being made. Further research and intensive
monitoring are needed to continue their protection.
There is also some concern about the wisdom of
concentrating nests in only one protected area. This
potentially exposes a large part of the remnant
population to disease, predation, or some other
catastrophe. The project will have to continue for
several years. Despite the overwhelming odds, those
involved with the Petrel Project continue to work
with the hope of preventing the extinction of these
wonderful birds.
March 1989
ACKNOWLEDGMENTS
NOTICIAS DE GALAPAGOS 23
We gratefully acknowledge the support ofFelipe
and Justina Cruz, Ing. Humberto Ochoa, Dr. Günther
Reck, Sylvia Harcourt, Dr. Richard Podolsky, and
members of the vocalization project in organizing
and supervising our role in the Petrel Project. Our
educational program in Galápagos depends also on
the enthusiasm of the students: Alison Downey,
Robin Gager, Wing Goodale, Charlotte Gray, Jane
Gray, Brian Hepler, Becky Lasky, David Lasky,
Alexandra Prime, Jane Prime, and David Tisch. A
special thanks to Bruce Rinker for co-Ieading this
course for many years.
LITERA TURE CITED
Baker, A.R. 1980. Report on breeding distribution
and population size of the Dark-rumped Petrel
(Pterodroma phaeopygia) on Santa Cruz Island,
Galápagos. Charles Darwin Research Station.
Bass, F. 1980. Report on the Dark-rumped Petrel
(Pterodroma phaeopygia) monitoring program
on Santa Cruz Island, Galápagos, 1980. Charles
Darwin Research Station.
Coulter,M.,D.Duffy,andS.Harcourt. 1982. Status
of the Dark-rumped Petrel on Isla Santa Cruz,
1981. Noticias de Galápagos 35:24.
Cruz, F., and J. Cruz. 1986. The campaign to save
the Hawaiian Petrel. Noticias de Galápagos 44:6.
Harris, M. 1970. The biology of an endangered
species, the Dark-rumped Petrel (Pterodroma
phaeopygia), in the Galápagos Islands. The
Condor 72:76-84.
Kress, S., and R. Podolsky. 1987. The role of
vocalizations and vacant nest sites as breeding
requirements of the Dark-rumped Petrel
(Pterodroma phaeopygia phaeopygia). Proposal
to Charles Darwin Research Station.
Rosi Dagit, International Student Research Inc.,
19989 Sischo Drive, Topango, California 90290,
USA.
FERNANDINA VOLCANO ERUPTS
Editor's Note.-The following report is adapted
from two issues of the SEAN Bulletin, the monthly
publication ofthe Smithsonian Institution' s Scientific
Event Alert Network (SEAN). This small group has
been reporting on volcanic activity around the world
since 1975. Readers interested in this aspect of
natural history, in Galápagos and elsewhere, should
know that the first 10 years of SEAN reports have
been recompiled, on a regional basis and with a
comprehensive index, as a 657 page book, to be
published in February by Prentice Hall and the
American Geophysical Union. Its title is Global
Volcanism 1975-1985, and publication information
can be obtained from the Scientific Event Alert
Network, NHB stop 129, Smithsonian Institution,
Washington,D.C. 20560, USA. Thefollowingreport
was written largely by Tom Simkin, Secretary for the
Americas (Science) of the Darwin Foundation, and a
vo1canologist with the Smithsonian since 1967.
Fernandina Volcano, Galápagos Islands,
Ecuador (0.37°S, 91.SS0W).-All times are local (=
GMT -6 hours). On 14 September an eruption of
Fernandina ended the longest period of volcanic
quiet in the Galápagos Islands in the last 20 years.
Fernandina' s last eruption was in March/ April1984
(see SEAN Bulletin vol. 9, no. 33), and no eruptions
have been reported from the Galápagos since then.
An unusual earthquake swarm was recorded by
the U.S. Geological Survey's (USGS) Worldwide
Seismic Station Network on 24 February 1988, and
the most recent epicenter locations place six events
within 25 km of Fernandina' s caldera. These took
place within a lO-hour period and were in the
magnitude range 5.0 to 5.5.
Two more recent earthquakes have also been
located within 25 km of Fernandina's caldera, a
magnitude 4.8 event on 15 April and a 5.3 event on
20 May. Inquiries following the 24 February swarm
revealed no observations of voIcanism by scientists,
residents, or tour vessel personnel in Galápagos, but
Fernandina is uninhabited and cannot be seen from
inhabited parts of the Archipelago. Inspection of
low-resolution satellite imagery found no Galápagos
plumes on 24 February.
On 14 September, residents of southem Isabela


In search of the Dark-rumped Petrel

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In search of the Dark-rumped Petrel

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