2006 Final Report on the Western Snowy Plovers

Coal Oil Point Reserve, Santa Barbara, CA

Contact for this report:
Cristina Sandoval
Marine Science Institute
University of California
Santa Barbara, CA 93106
Sandoval@lifesci.ucsb.edu
http://coaloilpoint.ucnrs.org

Site: Sand’s Beach , Coal Oil Point Reserve (COPR)
Location: RU5, Santa Barbara, CA
Lat-Long: 34 25 00 N, 119 52 30 W
USGS maps: Goleta 7.5, Dos Pueblos Canyon 7.5, Goleta 15
Jurisdiction: Owned and managed by the University of California Santa Barbara.
Climate: Avg precip 14-21 in/year, avg min temp 42 F, avg max temp 75 F
Total linear beach length: 1,200 m
Protected linear beach length: 400 m during Winter and fall and 800 m during the breeding season
Protected area during breeding season: 30,700 sq meters or 7.6 acres
Docent program? Yes, all year, most daylight hours
Interpretive and regulatory signs? Yes, at beach entrances and along protected areas
Management Plan? Yes
Enforcement? Docents request compliance with leash law and restricted areas. Officers are called when problem is not solved.
Monitoring: Yes, weekly in the winter and Fall and daily in the spring and Summer.
Predator management: harassment of crows, fencing to prevent skunk.

Abstract

In 2006 we continued with the management of the WSP population at Coal Oil Point Reserve as in previous year. We abandoned the use of mini-exclosures after Great Horned owls cued in the exclosure to pursue adult plovers. We continued to raise chicks from destroyed or abandoned nests and banded the 10 chicks that fledged in captivity. 48 chicks fledged at the beach and another 11 fledged in our nursery. This was the largest number of fledglings since management started in 2001.

Introduction

Sands beach at Coal Oil Point Reserve (COPR) has a wintering and a breeding population of the Western Snowy Plover. The beach is open to the public all year, but a portion of the dry sandy beach, which is the plover habitat, has been protected since Spring 2001. Presently, all of the potential breeding habitat is protected during the breeding season and the beach east of the slough mouth is protected during the wintering months. Although Sands beach is relatively small, it has a large population of wintering plovers.

Methods and Results

The 2001-2004 report (Sandoval, 2004) describes the management actions taken to protect the wintering and breeding populations of WSP at the reserve since 2001. Figure 1 shows the location of the plover habitat and the permanent and seasonal fences to protect them.

Figure 1. Location of the habitat protected for the Western Snowy Plovers on Sands beach at Coal Oil Point Reserve.

Wintering Population

In 2006 we have counted plovers regularly as in 2005. When we counted, we walked along the wet sand from the eastern boundary of Sands beach to the western boundary of the Reserve (Figure 1) spotting and counting plovers with a binocular. All plovers, including those feeding near the shore, were counted. Color bands were also recorded and photographed when possible. Several banded plovers were observed during winter. A list of the bands sighted and the dates observed are listed in Appendix 1.

Breeding Population

Nesting

The number and location of adult plovers, nests, and chicks was counted 2-3 times per week by Cristina Sandoval, during the breeding season. The maximum number of plover pairs observed in 2006 was 30. 43 nests were found and, of those, 24 successfully hatched at least one chick ( 75% ) (Table 1). The number of chicks per male was still was 2.8 in 2006.

Table 1. Changes in breeding at Coal Oil Point since 2001. All values represent totals for the year except the pairs column, which represents the peak number of nests at one point in time.

Figure 2. Number of fledglings at Coal Oil Point Reserve. Triangles are the number of chicks naturally fledged at the beach. The diamonds included the chicks fledged at the nursery.

We used mini exclosures for the 3rd year but removed all exclosures after we observed owl predation on some adults (Table 2).

Table 2. Fate of nests with or without exclosures in 2006.

Table 3. Fate of nests with or without exclosures between 2004, 2005, and 2006.

Hand Raised Chicks

Eggs from abandoned or destroyed nests were brought to our plover nursery and incubated at 99.5 degrees F until hatching. After hatching, they were transferred to a terrarium measuring 2 ft wide, 4 ft long, and 1.5 ft tall. After 3-5 days, they were moved outside of the building into an aviary 5.5 ft wide x 16 ft long x 7 ft tall. At night, the chicks were moved back to the building until 2 weeks of age. After that, they were left to sleep outside, in a closed wooden box. The chicks had a source of heat from a warm lamp at all times. They were released back to the beach when they were 35 days old, or until they tails were fully developed. The chicks were fed beach hoppers at libidum and meal-worms, as a treat, once a day. The beach hoppers were collected daily from under kelp wrack on the beach. They were also offered (but rejected) bloodworms and cat food. 

Most eggs that were collected came from nests abandoned after the nest was buried by sand during strong wind (Table 4).

Of the 18 eggs collected 14 hatched (Table 5). In 2006, we did not determine if the unhatched eggs were infertile because we sent these eggs to the laboratory for a study of mercury contamination. One of the unhatched eggs one chick that died while piping. Of the 3 chicks that died after hatching, 2 died right after hatching and one did not thrive and eventually died.

Table 5. Fate of abandoned eggs collected from the beach to be hand-raised.

Predation

Great Horned Owls were one of the main causes of adult mortality in 2006, particularly in nests protected by nest exclosures (Figure 3 and 4, Table 2). We promptly removed the exclosures after the first evidence of owl predation on adults. It is likely that the owls also preyed upon on adults of the 3 nests that did not have exclosure and were abandoned. Unfortunately, the owls may not live a footprint when there is not an exclosure so we cannot confirm this hypothesis.

A meshed skunk fence was again used to help prevent skunks from moving from inland to the beach. Only 2 nests were eaten by skunks in 2006 (Table 6), compared to 18 in 2005. We don't know why 2006 had a low nest loss by skunks.

Table 6. Number of nests lost by fate