Monthly Archives: May 2003

Underwater Transect at Race Rocks

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The most difficult transects to do at Race Rocks Ecological reserve are those underwater. Through the years we have done a number of these, mostly in training sessions with the Pearson College Divers.  We experimented with various types of spools for laying out a line, types of weighted line, measuring tape, quadrat sizes, types of underwater paper on clipboards, types of pencils or writing devices  etc.  The best arrangement was using a 30- 50 metre long tape which could be attached to the peg on shore  and then taken out by the diver in a predetermined compass direction. The biggest problem other than the narrow window to get the work done was always the kelp cover, making the process very difficult in the later part of the year when the Nereocystis, (bull kelp) cover would make it impossible to access some areas.   The divers working in pairs would then proceed along one side of the line producing a record of the belt transect.  

Laura Verhegge and students of Pearson College doing an underwater transect off peg #1 at Race Rocks.

 


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Return to the Contents page for Environmental modelling with Transects..

Tidepool # 10 at Race Rocks

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In May 2004 the biology class measured features of several pools, including this one, pool 10.

This file has been started to present some of the information we have accumulated on the pool in order to stimulate students to raise further questions and devise problems that can be investigated at the pool. It is also intended to be part of a cumulative digital legacy that those examining the pool can pass on to future students.

This pool has a diameter of less than half a meter .This pool is characterized by having a base of white crystalline quartz. It is also shaded for much of the day, and is usually filled with harpacticoids.

white quartz with harpactacoids visible

SEE THIS REFERENCE in the Race Rocks Taxonomy on Harpacticoids

A large amphipod and the small red harpacticoids in pool 10

Limnodromus griseus: Short-billed Dowitcher–The Race Rocks Taxonomy

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Short -Billed Dowitchers, photo by Riley Strother, April 20 2017

This juvenile short-billed Dowitcher was seen up near the tower in August 18 2009. It was very tame and quite unconcerned with the local humans. Image by Ian Perry.

The same juvenile, (Aug 18/ 09) , shown above. Images by G.Fletcher
Dowitcher probing for invertebrates Note the Halosaccion band of the intertidal zone where it is feeding rear view- note buff colored underparts side view- note dark eye.
Eukarya
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Aves
Order Charadriiformes
Family Scolopacidae
Genus Limnodromus
Species griseus
Common Name: Short Billed Dowitcher

The Short-billed Dowitcher breeds in Northern Canada. It winters in South America.
It occurs rarely and solitary at Race Rocks where it stops on migration. Short-billed Dowitchers normally are birds of mudflats along the Pacific Coast. One individual bird was filmed on May 1 2003 (above)as it probed for food among the barnacles and algae of the Halosaccion zone at Race Rocks.

In the photo to the right from September 2005, another dowitcher roamed through the area near the base of the rock on the East side. So presumably we have pictures of the stopover going North and South!

Compare with the size of a gull in this Link to a post showing Dowitchers at Race Rocks-April 20 , 2017

This video shows the Short-billed Dowitcher (Limnodromus griseus) in the intertidal zone to the East of the docks at Race Rocks. Note the “sewing machine ” action as it probes for food. The biology class watched this bird on May1/03 before starting on an intertidal transect in the same area. The coloration was noticeably buff-colored when compared to other shore birds. This individual was very fearless, even returning to feed briefly nearby after we had laid down our transect. This is normally a bird of the Pacific Coast mudflats.

 

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. May 2003– Garry Fletcher/strong>