UCR BIOL X431.8: Natural History of the Channel Islands

31 May 2013-2 June 2013

Kurt Leuschner, Instructor


Recommended Text: Schoenherr, Feldmeth and Emerson, Natural History of the Islands of California (1999)


Friday, 31 May 2013

            Meeting in the breakfast room of the HI at 6PM.  Introduction covering the Bight of California (roughly from Point Conception to San Diego) and some oceanography.  Complex geology including volcanic origins and sedimentary layers as well.  Brief discussion of continental versus oceanic islands including the concept of island biogeography introduced by Robert McArthur and E. O. Wilson who suggested “an equilibrium determined by the balance between immigration rates and extinction rates.”[1]  Introduction to the SLOSS debate—the role of a single large island versus several small islands in “conserving biodiversity in a fragmented habitat.”  For example, the largest island, Santa Cruz, has the most biodiversity.  Moved on to methods of colonizing: 1) land bridge, 2) swimming or flying, 3) rafting (the most notable reported example being a live, but emaciated jack rabbit (Lepus californicus or bennettii) found floating on a 40x25 foot pelagic raft of giant kelp (Macrocystis pyrifera) near Lat. 33 degrees, 13 minutes N and Long. 118 degrees, 45 minutes W (defining the basin between Santa Catalina, Santa Barbara and San Clemente Islands), the latter being the closest island, but still 39 miles (62 km) “from the nearest point of the California coast” in August 1955,[2] 4) air flotation, 5) passive transport, and 6) vicariant transport.  Brief discussion of likely animals which could be seen, given that there are about 1,000 possibilities including 12 endemic animals such as Santa Cruz Island Deer Mouse, the Anacapa Deer Mouse, and the Santa Cruz Scrub Jay (see role of AOU) and birds such as bald eagles, house finch, Bewick’s wren, orange-crowned warbler, logger head shrike (the SCI has only 13 but seems to be making a comeback) and plants such as the giant coreopsis.  Then, the issue arose of island gigantism (and reasons for it such as more prey, better efficiency with water, especially retention, better dispersal and finally, fewer competitors) as opposed to insular dwarfism (and less resources, so you are smaller, no trees/cover so less places to hide).  Note Cope’s Rule about organisms getting bigger over evolutionary time.


Field Notes:


Saturday, 1 June 2013

9AM departure on “The Island Adventure” with Island Packers with Laurie, Dede and Joel, as staff guides.  Overcast—light coastal fog aka June gloom, no wind (in harbor, but a 20MPH head wind out in the channel), calm water.  Sat on the starboard side, upper deck under the canopy as per Larry Loeher[3] suggestion.  Birds: peregrine falcon (on mast in harbor), blue heron, western grebe, double crested cormorant, surf scooter, barn swallow, oyster tern, Brandt’s cormorant, California brown pelican, red-necked phalarope, Sooty Shear Water (Puffinus griseus), raven, pelagic cormorant, pigeon guillemot, and dolphins off the stern as we left the harbor. 

Arrived at 11:30AM at Prisoners Harbor[4] of Santa Cruz Island.  High tide will be 4PM.  Cool, fog.  Dr. Carey Stanton died on the island in 1987 and is buried in the island chapel yard.  An 1887 building made from local materials.  Saw the endemic scrub jay.  Trail upward with Joel as our guide toward Pelican Bay: island buckwheat versus SCI buckwheat (with light/dark green leaves), coastal sagebrush, spotted towhee (Pipilo maculatus), agave, red gum eucalyptus, fennel, coyote brush, island morning glory, giant coreopsis, more coastal sage, Northern flicker, monkey flower, Live-forever (Dudleya cymosa), silver lupine and deer weed (both good nitrogen fixers), manzanitas, oak (gargled trunks), acorn woodpecker, scrub oak, lemonade berry, osprey, summer holly (red berries not to be confused with toyon-- Heteromeles arbutifolia), bishop pine (tight cones), Ceanothus (island lilac, purple berry seed pod), Humboldt’s lilies (Lilium humboldtii), old man’s beard (indicative of good air quality), lizards (including western fence and side blotched), hazardia, ironwood tree (something like 13 clones extant), and western fence lizard (Sceloporus occidentalis). Late lunch break with a good view; just after lunch at 2PM, medical evaluation Joel (who is an RN as well!) of classmate by who lost her footing and tumbled over the edge of the trail; small gash on right ear.  3PM arrival at large oak and have to turn back before Pelican Bay, if we are to leave island today; maximum gain in elevation was about 400 feet.  In the distance, we could hear the foghorn of a container ship, which is required to sound it every two minutes.  3:47PM I saw the island fox and pointed it out to Dede and Nance.  Nance and I discussed the odd scat behavior of the fox, which seems much more feline like, based our AB tracking classes.  4:03 departure with a 5 foot tide; discussion of binoculars--Kurt likes the 8x42 Vortex Crossfire and suggested we might visit Optics4birding in Irvine.  The captain maintained a steady 1850-1860 RPM on the way back to the dock.  Dinner at Capriccio’s in downtown Ventura with Kurt and Nigel Hunter, head of development for the East African Wild Life Society who is in the US working on developing ideas on to disseminate “SWARA: The Voice of Conservation in East Africa,” more widely.


Figure 1. US Coast Survey, 1854; engraving by J. A. Whistler

who lost his job for unauthorized inclusion of Western gulls in this image

Sunday, 2 June

 9:20AM with fog—marine layer, calm, 66 degrees.  Under way to Anacapa Island on the “Vanguard,” we saw three Mylar balloons (but didn’t pick them up like the two we did yesterday), a couple of sea lions and fourteen pelicans flying in a v-formation.  At the Arch by 10:40AM, landed at the East Anacapa Landing Cove, and at 11AM had an orientation about nesting behavior/dive-bombing of gulls (if they are squawking, then keep walking!) and the 1932 buildings in the style of a Mexican fishing village; early history includes a 1853 shipwreck and a 50 foot beacon by 1912; 1938 established as a National Monument and then a National Park in 1980.  Nothing very large on this island.[5]

The island is either one big colony of western gulls or giant coreopsis, or both because some gulls sit on top of them.  No sexual dimorphism among gulls.  Typically 2-3 eggs; chicks are spotted like their eggs—good camouflage.  Red spot on mother may be a target for chicks to peck and get fed.  About 50% survival rate in first year.  Threats: red-tail hawks, ravens, and each other.  Aka “garage gulls,” because they go to the city dump and fly back and regurgitate BBQ bones rather than squid.  Also saw pelagic cormorant and pigeon Guillemot at the cove.  A beautiful female yellow warbler and song sparrow at the Visitor Center; later, a savannah sparrow (Passerculus sandwichensis) and we watched an oyster catcher for a long time.  Gum weed (yellow flower used by the Chumash as a salve). Bush mallow (endemic), non-native crystalline ice plant (from Africa, which is salt tolerant), Island buckwheat, and prickly pear.  Extensive midden site, at least two feet deep; Chumash visited this site repeatedly because of the wonderful view, but most likely would have to have brought their own water—a small supplement could be obtained at a nearby cave, but perhaps only one-to-two gallons per day.  At Inspiration Point (1.5 miles roundtrip), we could see a cave on the cliffs in the distance, where 3 peregrine falcon chicks were nesting.  On the return, talked with Sarah Chaney (NPS restoration biologist) about ironwood; she says that she has seen 2 or 3 seedlings when two different clones come together—they do produce seeds and they are viable.  She thinks this introduction would be a good restoration strategy.  Walked up to the lighthouse, but can’t get too close due to potential hearing damage.  Prompt 3:02PM departure from dock; overcast. Sea lion nearby.  Went to the south side, around the arch for seals; saw a shortfin mako shark (or, less possibly, it was a blue shark (Prionace glauca), given its behavior, not so likely). Sighted a porpoise at 4:17PM as we entered harbor.  Thinking about likely topics for exam and doing a species profile on ironwood and/or jay.


Useful resources:


58 photographs at https://plus.google.com/photos/115191388542813037913/albums/5885388777701068049/5885388827759156354?authkey=CM6qk-z-ypiYPw&pid=5885388827759156354&oid=115191388542813037913 (accessed 3 June 2013).


Bill McCawley, “Native Plant Garden: Guide to Island Plant Adaptations” (July 2007).

Bill McCawley, “Native Plant Garden: Guide to Island Chumash Indians Plant Usage” (undated).

“The Nature Conservancy Interpretive Trail Between Prisoners Harbor and Pelican Bay” (undated).

NPS, “Channel Islands” (undated).

NPS, “Channel Islands: Hiking Eastern Santa Cruz Island” (undated).


Created: 3 June 2013; revised: 5 June 2013.

[1] Jared M. Diamond, “Avifaunal Equilibria and Species Turnover Rates on The Channel Islands of California,” Proceedings of the National Academy of Sciences 64 (no. 1, September 1964): 57-63.


[2] First reported in the professional literature by J.H. Prescott, “Rafting of a Jack Rabbit on Kelp,” Journal of Mammalogy 40 (1959):443-444.


[3] Serendipitously sitting next to him on Thursday at the Fiat Lux luncheon, I discovered he has been out to the islands something like 90 times—physical geography background.


[4] In an attempt to increase its population, Mexico sent 40 prisoners to Santa Barbara and they were sent to this island; hence, the name.


[5] Even the non-indigenous rats have been removed—see “Island Recovery Evident Ten Years after the Removal of Rats” at http://www.nps.gov/chis/parknews/anacapa-island-recovery.htm (accessed 3 June 2013).