Tag Archives: cormorant

Phalacrocorax pelagicus: Review of Research on Nesting and Populations

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rmpelagic1We have seen a marked decline in nesting of one of the four species of seabirds which has nested traditionally at Race Rocks, Pelagic Cormorants (Phalacrocorax pelagicus). By 2007, the nesting population had been reduced to one or two nests, and from 2008 to the last season (2009 ) there were no nests at all. This population crash has been common across the Gulf Islands., and the lower end of Vancouver Island and Strait of Juan de Fuca. According to the Canadian Wildlife Service, the population of this species is estimated to be at 9000 individuals, and the pelagicus subspecies is red-listed by BC – other subspecies are stable.

In this file, I have summarized the results of several papers on research on Cormorant populations in the southern Gulf Islands and Georgia Strait. Vermeer and Rankin, 1984, did their research when the populations were on the incline, however since the 1900s, this trend has not persisted as has been reflected in the paper by Chatwin et al. The summary of their paper and the possible reasons for decline are listed near the end of this review.

The British Columbia Coastal Waterbird Survey by Badzinski et al, 2005 indicated a possible upturn in the population trend in BC.

See images of Pelagic Cormorants on Ryan Murphy’s Flickr site

The Christmas bird count records from Race Rocks reflect some of the low population numbers at that time of year, but do show an increase in the last two years, so we hope this may signify a turn in the welfare of this species. It will be interesting to track whether or not this species returns to nesting.

Population Trends in Nesting Double-Crested and Pelagic Cormorants in Canada

  • Author(s): Kees Vermeer and Leo Rankin Source: The Murrelet, Vol. 65, No. 1 (Spring, 1984), pp. 1-9 Published by: Society for Northwestern Vertebrate Biology Stable URL: http://www.jstor.org/stable/3534203 (partial listing only)
  • ABSTRACT- Breeding populations of Double-crested (Phalacrocorax auritus) and Pelagic Cormorants (P. pelagicus) were surveyed in the Strait of Georgia, British Colum-bia, in 1983. Double-crested Cormorant numbers have increased 2.4-fold and Pelagic Cormorant numbers 1.1-fold since 1975. Double-crested Cormorant populations are presently not only increasing in British Columbia but all across Canada and in the northeastern United States. These increases are thought to be the result of decreased disturbance and persecution by man.
  • The following table is presented in partial form only:
Double-crested and Pelagic Cormorant Inventory in the Strait of Georgia in 2000

  • http://www.env.gov.bc.ca/wildlife/wsi/reports/4382_WSI_4382_RPT.PDF (see complete report)
    Authors:    Trudy A. Chatwin, Monica H. Mather, Tanya Giesbrecht May 2001
    Abstract Since the early 1990’s Double-crested and Pelagic Cormorant have shown alarming declines in nesting populations in the Strait of Georgia. This study was initiated in 2000 to provide a complete count of nesting colonies in the Strait and compare population estimate from counts completed in various years since the mid 1950’s. A complete survey of all colonies was done in 1987. Before that, counts were done in many colonies, though not annually. We surveyed 34 Pelagic Cormorant and 17 Double-crested Cormorant historic and current colonies during the 2000 breeding season. Where possible we examined nest population trends at colonies with multiple years of data. Our analyses showed that overall counts of Pelagic Cormorants were down by half and Double-crested Cormorants had declined by two-thirds since 1987. Pelagic Cormorants showed a significant decline in total nests between 1959 and 2000; although during that period, an increase in the population at Mitlenatch Island was noted. At Double-crested Cormorant colonies, two significant increasing trends were noted. Since 1983 the population at Shoal Islands has slowly increased from zero to 104 nests in 2000. Likewise the population at Mitlenatch has also increased from zero to 70 nests. However these increases do not offset the very dramatic declines in overall population size. The most profound decreases were seen at Mandarte and Great Chain Islands where most of the Double-crested Cormorants were nesting in the late 1980’s. At Mandarte Island, 1100 nests were observed in 1983, while only to 215 were counted in 2000. We suggest that the causes of declines are possibly related to a combination of Bald Eagle disturbance, change in prey availability and human disturbance. Recommendations for management and conservation are discussed.
  • The following table is presented in partial form only:
The authors express their concern for the decline in recent years with the following summation:

  • “Based on nest counts, the nesting populations of Pelagic and Double-crested Cormorants in the Strait of Georgia have shown alarming declines in the last few years. Concern is especially warranted when one compares the complete counts that were made in 1987 and 2000. The number of nests observed has decreased by 54% for Pelagic and 70% for Double-crested Cormorants. “
The reasons for the decline were summarized in the paper as follows:

  • “The populations of both cormorant species have fluctuated considerably over the 40 years of surveys. This could be due to changes in prey availability in the Strait. Cormorants feed on Pacific Herring, Gunnells, Shiner Perch and Salmon. It has been suggested that herring schools have moved north in the Strait of Georgia (Jane Watson, Pers. Comm.), which could account for the increase in both species of cormorants at Mitlenatch. However, this does not account for the loss of the Hornby Island Colony as there is a major herring spawn in that area. As well, it is difficult to explain the increase in the Shoal Islands Double-crested Cormorant colony, by shifts in herring populations.
    Other concerns for nesting cormorants are predation by Bald Eagles (Haliaeetus leucocephalus) and disturbance from boat traffic. Eagle populations have increased on the east side of Vancouver Island (Karen Morrison, Pers. Comm.). Giesbrecht (2001) showed that Eagles were the main source of disturbance to nesting Double-crested Cormorant ’s in the Strait. She observed eagles flushing birds from their nests as well as direct predation on adults/juveniles. Recreational boating and kayaking have also increased in the Strait of Georgia. Although Giesbrecht (2001) did not observe flushing by boaters in her study, anecdotal information (Moul 2001) indicates that human disturbance either by landing at a colony or flushing birds by approaching too closely exposes chicks and eggs to predation by Northwestern Crows (Corvus caurinus), Glaucous-winged Gulls (Larus glaucescens) and Bald Eagles. “
British Columbia Coastal Waterbird Survey An Evaluation of Survey Power and Species Trends after Five Years of Monitoring March 2005http://www.bsc-eoc.org/download/BCCWS%205-YR%20Report.pdf

Authors: Shannon S. Badzinski 1, Richard J. Cannings 2, Tasha Smith 2, & Jason Komaromi 3

  • Data for two of three species of cormorants show increasing trends (Double-crested
    Cormorant, Pelagic Cormorant). Both these species have shown significant declines in numbers
    at breeding colonies on the British Columbia coast between 1980 and 2000, so the results from
    this survey may indicate a stabilizing trend but further monitoring is clearly needed. Brandt’s
    Cormorants, which occur primarily as a non breeding species, show no clear population trend
    over the past 5 years.
Also from the website of the Canadain WildlifeService, Information is presented on the decline of seabirds along the Pacific Coast of Canada. So we will continue to update our population observations of this species .Garry Fletcher, February, 2010

Phalacrocorax auritus: Double crested cormorant

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Double Crested Cormorants are winter residents at Race Rocks. They nest on other islands off Victoria.

Domain Eukarya
Kingdom Animalia
Phylum Chordata
Sub-Phylum Vertebrata
Class Aves
Order Pelicaniformes
Family Phalacrocoracidae
Genus Phalacrocorax
Species auritus
Common Name: Double Crested cormorant

Other Members of the Class Aves at Race Rocks.
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

Phalacrocorax pelagicus: Pelagic cormorant–The Race Rocks Taxonomy

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rmpelagichorm

Pelagic Cormorant,  Phalacrocorax pelagicus photo by Ryan Murphy, 2010

See images of Pelagic Cormorants on Ryan Murphy’s Flickr site

Range of the Pelagic Cormorant:
Breeds from the Bering Sea to Japan and south to near San Diego, USA.  Winters in the Aleutian Islands and along the coast from British Columbia to Baja, California.

Pelagic cormorants nest at Race Rocks and live there year-round. They prefer the cliff to the West of the camera 5, and can often be seen perched there along the cliff edge (picture above left)

Nest:
The nest is a mass of seaweed and grass on a cliff.  Pelagic cormorants nest in colonies and like ledges so narrow they must land and take off facing the cliff. During the years between 1980 and 1995 numbers of nests ranged above 20. In the years 2000, 2001,2002 there was complete nest failure due to the lack of herring feed in the surrounding waters. During 2003 , 2004, and 2005 only two or three nests have been established with successful hatches.

Following  are pictures taken in the nesting season by G.Fletcher in the 1980s and 1990’s when there were pelagic cormorants nesting at Race Rocks:

Local Numbers of Phalacrocorax pelagicus
Xmas bird count

Screen Shot 2014-12-20 at 8.06.55 PM

Pelagic Cormorants–Ryan Murphy photo

Year
1997–14
1998–2
1999–20
2000–14
2001–12
2002–20
2003- no census taken..too stormy!
2004- 110

rmpelagiccorm22010

Pelagic Cormorant–Ryan Murphy photo

 

2005- 20
2006-20
2007-42
2008-storm
2009-90
2010-78
2011-0
2012-0
2013-17
2014—
rmpelagiccorm2010

Pelagic Cormorant–Ryan Murphy photo-2010

Classification:
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelicaniformes
Family: Phalacrocoracidae
Genus: Phalacrocorax
Species: pelagicus
Common Name: Pelagic cormorant

 

We have seen a marked decline in nesting of one of the four species of seabirds which has nested traditionally at Race Rocks, Pelagic Cormorants (Phalacrocorax pelagicus). By 2007, the nesting population had been reduced to one or two nests, and from 2008 to the last season (2009 ) there were no nests at all. This population crash has been common across the Gulf Islands., and the lower end of Vancouver Island and Strait of Juan de Fuca. According to the Canadian Wildlife Service, the population of this species is estimated to be at 9000 individuals, and the pelagicus subspecies is red-listed by BC – other subspecies are stable.

RM_males-and_female_pelagic_cormornat

Two males and a female pelagic cormorant

In this attached file, I have summarized the results of several papers on research on Cormorant populations in the southern Gulf Islands and Georgia Strait. Vermeer and Rankin, 1984, did their research when the populations were on the incline, however since the 1900s, this trend has not persisted as has been reflected in the paper by Chatwin et al. The summary of their paper and the possible reasons for decline are listed near the end of this review.

See other posts of Pelagic Cormorants at Race Rock

taxonomyiconReturn to the Race Rocks Taxonomy and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. Garry Fletcher, 2003

 

Cormorants vs eagle

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ood Evening
TEMPERATURE: Max. 9.5 ºC »» Min. 7.8 ºC »» Reset 9.4 ºC »» Rain 6.8 mm
MARINE LIFE: Although the forecasted high winds did not materialize most of the hauled out Sealions along the north shore of Gr. Race have taken to the water or moved farther inland to avoid the high swells coming in from the weather system to the east. This afternoon one mature Bald Eagle spent about an hour on the high point of West Race. The 200 or so Cormorants took to the air as the eagle landed but soon settled back down leaving a good distance between them and the great raptor.
HUMAN INTERACTION: 5 Ecotour boats and 3 pleasurecraft through today.
posted by Carol or Mike S at 6:09 PM
Good Morning
WEATHER: Sky Cloudy »» Vis. 15 Miles »» Wind North East 5 Knots »» Sea Rippled
posted by Carol or Mike S at 7:25 AM

Herring Balls

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TEMPERATURE: Max. 11.1 ºC »» Min. 7.7 ºC »» Reset 9.1 ºC »» Rain 0.8 mm

MARINE LIFE: There are fewer birds today, saw only 3 fish balls in the immediate area but could see a lot of activity quite a distance to the east with the scope.Still about 2000 gulls and Cormorants in the MPA.
HUMAN INTERACTION: Angus over in the Hyaku with Scott and Ken working still on the Camera 2 system, also 5 Ecotour boats.
posted by Carol or Mike S at 6:15 PM

Counted over 500 Cormorants just on North Rocks

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Good Evening
TEMPERATURE: Max. 10.2 ºC »» Min. 7.0 ºC »» Reset 8.1 ºC
MARINE LIFE: Another good day for sea birds feeding, thousands of birds from Whirl Bay and as far as you can see to the east , every rock including Gr. Race ‘covered’ in birds. Counted over 500 Cormorants just on North Rocks and the rocks to the Southeast and most likely at least that many in the kelp beds. Not many Sea Lions have hauled out, only 15 along the north shoreline of Gr. Race, a group of 11 Northern are bunched together on the high point just east of the house but are very edgy.Most of the animals hauled out are on the middle rock.The injured California Sea Lion was gone at first light and we have not seen him all day. There were 7 geese today.There is no standing fresh water but they do enjoy the greens. A small group – 5 or 6 – Transient Orca were hunting in the entrance to Pedder Bay and took at least one seal. There were several pleasurecraft and 7 Ecotour boats watching the kill. After the boats left the Orca moved west along the shoreline quite slowly and at times rested on the surface for 5 minutes at a time. It took them a good hour to go from the east tip of Bentinck Island to Whirl Bay, I guess they continued west but did not see them again.
HUMAN INTERACTION: There was 1 dive charter in the West Race area, 13 Ecotour boats and 7 pleasurecraft through today.
posted by Carol or Mike S at 5:59 PM

Rosedale Light misplaced!

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Good Evening
TEMPERATURE: Max. 13.7 ºC »» Min. 7.1 ºC »» Reset 10.3 ºC
MARINE LIFE: A perfect day for the thousands of sea birds feeding in the many fish balls, most of the action was some distance outside the reserve but many of the cormorants and gulls landed to rest in the kelp and along the shore. Birds coming and going all day, the fishing seemed good for the sea lions as well, saw several 8-10 lb salmon caught just off the end of the dock.
HUMAN INTERACTION: There were 22 Ecotour boats and 7 pleasurecraft in the reserve today. One pleasure craft – open aluminum Girgor, approx. 4metres long 14K 33165 4 persons onboard were fishing in the reserve between Gr. Race and North Rocks.Reported this infraction to Fisheries. Near noon noticed a tug towing a log barge very close to the Rosedale light buoy, shortly after could not see the buoy and recieved several calls on the marine radio from sports fishers that they also noticed the buoy missing. Sometime later ‘found’ the buoy about 1 mile southwest of it’s designated position. Called Coast Guard and hopefully they will soon reposition the buoy.
posted by Carol or Mike S at 6:37 PM
Good Morning
WEATHER: Sky Clear »» Vis. 15 Miles »» Wind East 7 Knots »» Sea Rippled
posted by Carol or Mike S at 7:22 AM

Orcas and whale watchers

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Good Evening
TEMPERATURE: Max. 13.9 ºC »» Min. 7.5 ºC »» Reset 11.1 ºC
MARINE LIFE: There were about 50 Cormorants in the reserve today some on North Rks. but the majority along the ridges of the Southeast Rks. There are also over 60 Heermann’s Gulls. The geese family landed for a very short visit- about 15 minutes- but the real excitement was provided by the Orca, believed to be T10 group, transients. First sighted was the large bull near William Head just before 11:00. The Orca spent some time in the entrance to Pedder Bay then moved along the shore of Bentinck Island.After a wait of 10 minutes or so they then surfaced midway between North Rks. and the dock. While watching for the whales we listened to some of the tour boat operators on the VHF reporting the animals movements for the benefit of other boat operators.As the whales made their way heading east in front of the station the ‘Wildcat’ was entering from the west and followed the whales and at one point were so close I thought they were going to run over top of them! The whales moved south along the edge of the kelp bed to the east of Gr. Race then west along the southeast rocks and Gr. Race quite close to shore .2 boats Pr. of Whales (princess) and SeaFun Safaris followed along even though they were well within the reserve’s southern boundary which is the Rosedale buoy.The whales moved through the reserve passed West Race to the Pedder Bay area again and then about 14:00 headed West. At last report they were near Secretary Island. With all the sea lions and seals in the water, some Northern Sea lions in tight groups following quite closely I expected the Orca to have a kill, but then there were all those boats coming and going and staying????? for hours!
HUMAN INTERACTION: There were 4 pleasure craft and 28 Ecotour boats through the reserve today.
posted by Carol or Mike S at 6:09 PM
Good Morning
WEATHER: Sky Part Clouldy »» Vis. 15 Miles »» Wind North East 5 Knots »» Sea Rippled
posted by Carol or Mike S at 7:14 AM

Turnstones and Orca

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TEMPERATURE: Max. 17.0 ºC »» Min. 9.9 ºC »» Reset 15.9 ºC
MARINE LIFE: several groups of 20 or so Cormorants are spending part of the day on North Rks. and the rocks on the southeast of Gr. Race. There are now about 60 Black Turnstones busy along the shoreline, you can often see them on camera # 3 hopping among the sealions foraging for sand fleas or beach hoppers.Most of the time though they are farther down on the beach where the food supply includes small crabs which they find by ‘turning over pebbles and small stones’ thus the name Turnstone.There was one identified transient Orca, a large bull known as Y1 through the reserve about 10 am. There were 4 or 5 other Orca with him including a calf. These transeints came in from the west between North Rks. and Gr. Race. They spent a while foraging about not far off the dock then circled Gr. Race rather slowly before moving off to the northwest. At about 11:15 heard a report from one of the Ecotour boats that there was a group of residents in the entrance of Pedder Bay, did see some tail slapping and breaching but too far away to identify any individuals.
HUMAN INTERACTION: Second Nature in with supplies this morning. While the Orca were in the reserve 4 boats followed them which is contrary to the guidelines. 3 of the boats were fishing charters ,Beasley, Adams and Island Outfitters. The 4th was an unidentified 5 or 6 metre open Lifetimer.
posted by Carol or Mike S at 6:12 PM

Aug21-24

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Saturday, August 24, 2002

Good Evening
TEMPERATURE: Max. 17.1 C  Min. 10.1 C Reset 15.0 C
posted by Carol or Mike S at 6:17 PM
Good Morning
WEATHER: Sky Obscured  Vis. 1/8 Miles Fog  Wind West 25 Knots  Sea 2 – 3 Foot Moderate  Remarks Vis. North West >> North East 2 Miles
posted by Carol or Mike S at 5:38 AM

Friday, August 23, 2002 Good Evening

TEMPERATURE: Max. 12.9 C  Min. 9.9 C Reset 10.8 �C

HUMAN INTERACTION: The fog finally lifted just before 11:00 and we counted 25 Ecotour boats, 2 sailboats and 1 dive charter,also station boat to Pedder Bay and return.
posted by Carol or Mike S at 6:19 PM
Good Morning
WEATHER: Sky Obscured  Vis. 1/8 Miles Fog  Wind West 19 Knots  Sea 2 – 3 Foot Chop
posted by Carol or Mike S at 5:37 AM

Thursday, August 22, 2002

Good Evening
TEMPERATURE: Max. 12.5 C  Min. 9.3 C C      10.7C
Very chilly with the fog in and out all day, heard boats going by but visibility too poor to see them.
posted by Carol or Mike S at 6:15 PM
Good Morning
WEATHER: Sky Part Cloudy  Vis. 10 Miles Vis. South East >> South West 3 Miles Fog Wind West 11 Knots  Sea Rippled
posted by Carol or Mike S at 5:26 AM
Wednesday, August 21, 2002
Good Evening
TEMPERATURE: Max Min. 10. Reset 12.C
MARINE LIFE: The gulls are spending less time ashore now preferring to fish from the kelp beds. A group of about 20 cormorants spent the morning on the east end of the southeast rocks and the black turnstones seem to favour the little east bay.
There were 7 Ecotour boats and 2 pleasure craft through today also the Hyaku was in with Angus and 2 guests.
posted by Carol or Mike S at 6:09 PM
Good Morning
WEATHER: Sky Part Vis. 15 Wind West 17 Sea Rippled
posted by Carol or Mike S at 5:33 AM