Tag Archives: predation

Feeding at Sea

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Tuesday, January 08, 2002
Good Evening
TEMPERATURE: Max. 10.3C  Min. 8.1C Reset 8.8C  Rain 16.0 mm
MARINE LIFE:The Bald Eagles started to arrive early in groups of 2 and 3 and by 8:30 there were 8 ( 1 mature ) sitting shoulder to shoulder along the ridge by the chopper pad.They were holding their wings at about a 45 degree angle as if to dry off.By 9am there were 17 eagles -4 mature- mostly on the southeast Rks. At 11:30 I noticed quite a number of birds flying around the Rosedale buoy,with the telescope we could see thousands of birds feeding in the tide line.There must be a lot of fish as the birds were active all afternoon.
posted by Carol or Mike S at 6:08 PM
Good Morning
WEATHER: Sky Overcast Vis. 8 Miles Rain Wind West 5 Knots  Sea Rippled Low South East Swell
posted by Carol or Mike S at 7:51 AM

Eagle predation on gulls

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-2002-01-06′, ’16:06:28′, ‘ Another good day for watching eagles, 23 altogether – 5 mature ).They were spread out along the ridges of West Race, North Rks. and The Southeast Rks. At 9:15 one mature eagle caught a juvenile gull just over the northwest ridge above the boat house,unfortunately the gull which seemed lifeless dropped and landed in a pile of drift wood washing against the shore on the west side of the boat dock. A group of gulls hurried to the area but with the breaking waves and some fair sized logs crashing about, the gulls were unable to get at the dead bird.The weather started to worsen with winds picking up to 22-27knts. from the northeast, and by 12:50 in moderate rain showers all but 2 eagles left the area.The 2 remaining -immatures) left just before 13:30 ‘, ‘Mike or Carol’, ’16:07:22 ,

23 Bald Eagles

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Sunday, January 06, 2002
Good Evening
TEMPERATURE: Max. 9.9C  Min. 7.9C  Reset 9.7C  Rain 10.2 mm
MARINE LIFE: Another good day for watching eagles, 23 altogether ( 5 mature ). They were spread out along the ridges of West Race, North Rocks. and The Southeast Rocks. At 9:15 one mature eagle caught a juvenile gull just over the northwest ridge above the boat house,unfortunately the gull which seemed lifeless dropped and landed in a pile of drift wood washing against the shore on the west side of the boat dock. A group of gulls hurried to the area but with the breaking waves and some fair sized logs crashing about, the gulls were unable to get at the dead bird.The weather started to worsen with winds picking up to 22-27knts. from the northeast, and by 12:50 in moderate rain showers all but 2 eagles left the area.The 2 remaining (immatures) left just before 13:30
posted by Carol or Mike S at 6:10 PM
Good Morning
WEATHER: Sky Overcast �� Vis. 15 Miles �� Wind North East 15 Knots �� Sea 1 Foot Chop Low East Swell
posted by Carol or Mike S at 7:31 AM

Eagles pursue cormorant

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-2002-01-05′, ’16:02:09′, ‘Most of the activity was in the air today starting quite early, just before 8 am with the arrival of 3 Bald Eagles.They settled on the ridge of the Southeast Rks. but after several flights over and around Gr. Race chose to settle on the high points of North Rks.The first arrivals were all immature and were soon joined by 12 more immatures and 4 matures. The Eagles were quite aggressively hunting birds. One cormorant was separated, in flight by 2 pursuing eagles – immatures) and at the last minute dropped into the sea. One of the eagles gave up at that point but the other circled the cormorant, stretched out it”s talons, skimmed over the sea and just before contact the quick thinking? definitely lucky cormorant dove below the surface.With 19 eagles the rest of the birds were on alert all day.As soon as an eagle would take flight most of the gulls etc. would also take flight,when the eagle landed so did the other birds, and so it went until the last eagle left at 16:25. We did not see any birds caught,nor did we see any prey being eaten’, ‘Mike or Carol’, ’16:02:50 ,

Bald Eagles on the hunt

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Saturday, January 05, 2002
Good Evening
TEMPERATURE: Max. 8.8C  Min. 7.7C  Reset 8.0C Rain 0.4 mm
MARINE LIFE: Most of the activity was in the air today starting quite early, just before 8 am with the arrival of 3 Bald Eagles.They settled on the ridge of the Southeast Rks. but after several flights over and around Gr. Race chose to settle on the high points of North Rks.The first arrivals were all immature and were soon joined by 12 more immatures and 4 matures. The Eagles were quite aggressively hunting birds. One cormorant was separated, in flight by 2 pursuing eagles( immatures) and at the last minute dropped into the sea. One of the eagles gave up at that point but the other circled the cormorant, stretched out it’s talons, skimmed over the sea and just before contact the quick thinking? definitely lucky cormorant dove below the surface.With 19 eagles the rest of the birds were on alert all day. As soon as an eagle would take flight most of the gulls etc. would also take flight,when the eagle landed so did the other birds, and so it went until the last eagle left at 16:25. We did not see any birds caught, nor did we see any prey being eaten.
posted by Carol or Mike S at 6:09 PM
Good Morning
WEATHER: Sky Cloudy  Vis. 15 Miles  Wind North 11 Knots Sea Rippled  Occasional Light Rain Shower
posted by Carol or Mike S at 7:26 AM

Orca predation and gulls

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-2001-12-20′, ’16:58:23′, ‘With the relatively calm sea today the hauled out Sea Lions slept the time away.The most action came from a few Northern Sealions on Southeast Rks. that went into the water to investigate the Orcas that came in from the West at 1:20pm.There was one bull,3 that could be females or juveniles and one fairly small one.It was really hard to get a good look as they didn”t stay on the surface very long.The whales made their way along the south shore of Gr. Race then veered out towards the Rosedale light buoy where they spent until 3:40 swimming back and forth with frequent tail slapping,breaching and slapping of flippers. 200+ gulls and 30 or so Cormorants stayed with whales I would guess feeding on any scraps floating about on the surface.Since the Orcas stayed well off shore,were quite ”noisy” and did not seem interested in the seals and sealions my guess is that they were residents. The last we saw of them they were headed SW. ‘, ‘Carol or Mike S’, ’16:08:56 ,

Haliacetus leucocephalus: Bald Eagle–The Race Rocks Taxonomy

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In November 2009, Ryan Murphy captured this set of images when a juvenile eagle was making his daily pass by to prey on a seabird. The juvenile california gull provides the meal for that day. Click the image to see a slide show video of this sequence..See the Eagle Set on Ryan’s Flickr site

Bald Eagles measure from 30″ to 43″ ( 76 to 109 cm) in length and from 70″ to 96″ ( 2 to 2.4 m) in wingspan. They have a high thin, chittering voice which contrasts with its magnificent appearance. Bald Eagle’s diet is primarily based on fish catching. It also eats carrion and crippled waterfowl. At Race Rocks, eagles frequently take adult Gulls and Pigeon Guillemots as can be seen in the accompanying images.

The adult Bald Eagle has a snow-white head and tail, the immature ones have brown head feathers which develop white underneath and gradually grow out over several years.
It was formerly found living all over North America. Hunting, poaching and the growth of civilization has had a negative impact in the Bald Eagle population whch has dimished considerably in the last decades. Nowadays it is found only in the Aleutians, Alaska, sections of Northern and Eastern Canada, British Columbia, Northern United States and Florida.

Its habitat is on or near seacoasts as well as close to large lakes and rivers, where the fish population is abundant. It nests in tall conifers, often old growth Douglas Fir or Cedar. Nests are common in the Southern part of Vancouver island. The closest to Race Rocks are on Bentinck Island and along Taylor Beach. The nests are renovated every year starting in January with new sticks, often ripped from tall dead fir trees. The eggs are white and come in groups of 1 to 3 each time.Its beachcombing , scavenging role, and the fact that it eats at the highest trophic level, can cause the Bald Eagle to accumulate pesticides in its body ( from contaminated fish and wildllife. ) The Bald Eagle population remains high in the rain forest coastal area of central and Northern British Columbia and Alaska.

This image comes from the slide show “Fresh Kill” It provides a closeup of an eagle whose head coloring is almost mature, but has not yet lost its dark speckling.
Reference: Miklos D. F. Uduvardy ,1977 The Audubon Society, Field Guide to North American Birds, Western region., Chanticler press, fifth edition: NY

 

The nictitation membrane is a transparent inner eyelid in birds, reptiles, and some mammals that closes to protect and moisten the eye. It is also called the third eyelid.
Pam captured these images of young eagles close to camera 5 in the spring of 2005 to help us demonstrate this adaptation.You can find further information about this feature at: http://ebiomedia.com/gall/eyes/protect.html

Bald Eagles in the Rain

 

 

 

 

Bad Hair Day for the Eagles

 

 

 

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. Carolina Munoz 1987

 

Mediaster aequalis: Vermillion star–The Race Rocks Taxonomy

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Mediaster in its habitat. Photo by Dr.A..Svoboda

Snail predation

 

Vermillion stars are seen frequently by divers in the 0-15 meter depth at Race Rocks.

 

Information.
Bright red (vermillion in fact) with large plates along its five arms. To 20 cm. Common just below the surface on low tides but hardly ever high and dry. These are abundant subtidally – you may find plenty after storms or extreme tides.

This Vermillion star male was emitting sperm while in the tank at Pearson College in early January 2004 . This went on for more than three hours. Millions of sperm are broadcast into the water where they may have a chance encounter with eggs which are simultaneously released into the current by the females. Of the great numbers of eggs and sperm released only a few are fertilized and actually make it to maturity. This is a good example of
r-selection in the population.

– http://www.wavelengthmagazine.com/1998/jj98neigh.htm

Mediaster aequalis is one of the smaller sea stars ranging in size from three to seven inches. It is found on many types of beaches at very low tides.

– http://www.geocities.com/oscmarinetech/Animals.htm#Vermillion%20Star

The vermillion sea star is common in shallow subtidal waters. Its feeding area stretches to nearly the tip of each arm on the underside. The vermillion star, so named because of its colour can be found from the Alaskan Peninsula, south to southern Caifornia.

Colour: Vermillion aborally, more orange orally; tube feet red to flesh colour.

Habitat: common on rocks shell, sand, gravel, pebbles and mud.

Feeding: diet varies with substrate and season; eats encrustin sponges and bryozoans on ock; seapen.

Reproduction: breeds from March to May; number of eggs in 65mm sea star estimated at 1,800 per year. the eggs measure 1 to 1.2mm and are bright opaqe orange. It is estimated that Vermillion sea stars reach sexual maturity within four years.

Speed: The sea star can move anywhere between 27 and 40 cm per minute.

Reference: The Sea Stars of British Columbia, Lambert, 1981, British Columbia Provincial Museum, Victoria

Other Members of the Phylum Echinodermata 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.

Dec 2001 Damien Guihen (PC yr 27)

Tour Boat Disturbance

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Wednesday, December 05, 2001
Good Evening
TEMPERATURE: Max 6.1C — Min 3.3C — Reset 4.9C — Rain 0.8 mm
HUMAN INTERACTION: Two groups of students came over in 2nd Nature this afternoon to learn the intricacies of the desalination plant that provides our fresh water. Two tour boats were in the reserve at 14:40 one of which did approach Middle Rock a little too close and caused some Sea Lions to take to the water. I think actually having people standing so high on an observation deck was very threatening to the animals. Garry happened to be in the tower so obtained this video of the disturbance:
http://www.racerocks.com/racerock/archives/videcotourimpact.htm
Sadly we have a dead marine mammal at the base of the ridge along the east shore of Great Race. Even with the telescope I cannot tell whether it is a Harbour Seal,an Elephant Seal or a California Sea lion and I can’t get close enough without disturbing the 50 or so Sea Lions and 2 Elephant Seals hauled out all around to make a positive ID.MARINE LIFE: At approximately 16:00 we saw 6 or 7 Orca just east of North Rocks, unfortunately it was too dark for filming but what a sight! There was one very large bull in the group and one quite small Orca, possibly a calf. They were breaching and slapping their tails and really churning up the sea. They started out in fairly large circles diving, porpoising and rolling and the large bull breaching quite often. After about 10 minutes the circles got smaller and they started swimming very fast on their sides with their dorsals at about a 45 degree angle to the water. They were quite low in the water and were sort of ‘plowing’ the water,back and forth,around and around.Finally with the telescope we did see the reason for all the activity, one unlucky California Sea Lion. Twice the Sea Lion was tossed in the air. We watched until it was too dark to see anything except a few white splashes. As all this was going on there was a group of 30-40 sea gulls circling over-head ready to snatch up any ‘crumbs’ that might come their way -nothing is wasted in this example of the food chain.
posted by Carol or Mike S at 6:08 PM
Good Morning
WEATHER: Sky Cloudy — Vis. 15 Miles — Wind North West 5 Knots — Sea Rippled
posted by Carol or Mike S at 7:19 AM

Bald Eagle takes seagull

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Monday, December 03, 2001
Good Evening
TEMPERATURE: Max 7.1C — Min 4.3 Reset 4.7C — Rain 0.6 mm
Marine Life:Three mature Bald Eagles arrived in the area this morning about 11:15 ,one perched on the ‘look-out’ log on N.Rks while the other two shared a high point on the SE Rocks. all was quiet for over an hour when one of the two took flight, circled the rock twice,swooped behind the rock and reappeared with an immature gull in it’s talons.As the eagle with the gull landed the other two eagles started harassing the successful hunter to the point the it flew off leaving the now dead gull.I expected to see the other two eagles move in on the prey however they just remained on the ridge about a metre away from the gull just watching.Finally the third eagle came back,the other two took flight and the three eagles spent about 5 minutes flying at each other often with their talons out-stretched.At last one eagle left the fray swooped down made an unsuccessful grab for the gull then just continued flying north towards Pedder Bay.The other two flew over to West Race, sat there about 10 minutes then flew off towards Whirl Bay.Why the eagles left the gull I don’t know but it did not go to waste as the ever vigilant crows soon moved in for a meal!
A Great Blue Heron spent 11/2 hours in the East Bay area just below the tower then flew off towards Pedder Bay.Also a group of Black Oyster Catchers arrived just at sunset and settled among the rocks on the east side of Gr. Race.
posted by Carol or Mike S at 6:10 PM
Good morning
WEATHER: Sky Cloudy — Vis. 15 Miles — Wind West 7 Knots — Sea Rippled — Occasional Light Rain Shower
posted by Carol or Mike S at 7:32 AM