June 20, 2023

For immediate release

Contact: Myrna Hayes, President/Executive Director, Mare Island Heritage Trust
CELL PH: 707-249-9633
EMail: myrnahayes@mac.com


11th Annual San Francisco Bay Osprey Days

Free public event highlights osprey nesting on San Francisco Bay with Guided Hikes, Car Caravans and Presentations

Headquartered on Mare Island, Vallejo, California

[VALLEJO], CA – Friday, June 23, Saturday, June 24 and Sunday, June 25, 2023 the 11th Annual San Francisco Bay Osprey Days will take place at the Mare Island Shoreline Heritage Preserve and other locations throughout Mare Island in Vallejo. Mare Island is the San Francisco Bay’s epicenter of osprey nesting. By late June, it will be teaming with recently fledged young osprey in the sky and perched on high spots in the vicinity of their nest sites. There is no cost or preregistration required to attend the in-person field trips. Details can be found in the PDF attached, which will be posted on the Mareislandpreserve.com website and at the Mare Island Shoreline Heritage Preserve Facebook page.


Two-hour guided boat trips departing the Vallejo Marina are $45 per person and do require advanced registration with Dolphin Charters.  The free event features numerous car caravan and walking tours scheduled all three days led by field guides from the local Napa-Solano Audubon Society and other naturalists and the Mare Island Heritage Trust volunteer team.

Guided hikes in the Mare Island Preserve and car caravan tours of nest sites throughout Mare Island

Starting Friday morning, at 8:00am, Fairfield resident, Bill George, former Mare Island Shipyard worker and avid “unofficial” photographer of the Mare Island Preserve, will guide a free walk in the Preserve on the lookout for osprey and other wildlife to photograph in the one hour 1/2 mile walk. Meet Bill at the parking lot, 167 O’Hara Ct. Friday, June 23, 10am-11:30am, Vallejo resident, Michelle Eliker, Birding Expert, will guide an osprey viewing walk in the Mare Island Preserve. Meet her at the parking lot at 167 O’Hara Ct. in the Preserve. Vallejo resident and Naturalist, Marcia Grefsrud, will guide a osprey viewing walk in the Mare Island Preserve beginning at 1pm, following the same 1/2 mile route and meeting at the parking lot of the Preserve, 167 O’Hara Ct. on Mare Island. Myrna Hayes, Osprey Days Co-founder and Co-founder and volunteer Mare Island Preserve manager from 2007-2019 will host the boat trips and a Saturday  evening gathering with short walks to view an active osprey nest. Sunday, June 25, Robin Leong, Napa-Solano Audubon Society field guide, will lead a car caravan, from 11:45am-1:30pm. Meet Robin at the Mare Island Shoreline Heritage Preserve Entrance Park, Correa Ct @ Azuar Dr. at the South end of Mare Island in Vallejo.

“We really want people taking the tours to understand how critical it is to permanently protect the wildlife and cultural history of the southern Mare Island Shoreline Heritage Preserve area of Mare Island and to work to protect osprey and other bird nest sites throughout Mare Island”, said Myrna Hayes.

Osprey viewing boat tours of the Mare Island Strait/Napa River with Dolphin Charters

Four,  2-hour boat cruises are scheduled by Dolphin Charters on both Saturday and Sunday. “With 4 trips, we hope to accommodate everyone who wishes to view osprey easily visible along the Mare Island and Napa River/Mare Island Strait shoreline”, said Barbara Fitzgerald, of Dolphin Charters. Seating is still available for all tours. Departure times from the Vallejo Marina for the 2-hour osprey viewing boat trips are, Saturday and Sunday, 9:00am-11:00am and 1:00pm-3:00pm. The cost is $45 per person. Pre-registration is required. For Reservations: call 510-527-9622 or 800-472-9942 or visit dolphincharters.com

Osprey nesting on San Francisco Bay is still considered a new phenomenon

Until recently, osprey have been described as occasional visitors to San Francisco Bay by wildlife management agencies. Yet, the number of nesting pairs on the Bay and in particular at the confluence of the Napa River/Mare Island Strait and the Carquinez Strait on and near Mare Island have captured the attention of the Golden Gate Raptor Observatory and local Audubon Societies, particularly the Napa-Solano Audubon Society and the Golden Gate Audubon Society, as well as National Wildlife Refuge personnel. Osprey have been nesting in very small numbers for more than a decade in the Bay, flourishing in San Francisco Bay since the early 2000’s when the first successful nesting pair took up residence at the southernmost tip of Pier 34 at the mouth of the Napa River in the Mare Island Shoreline Heritage Preserve. The number has tended to remain stable or grow each nesting season.

In 2022, 19 nest sites were documented on the Napa River/Mare Island Strait, with 56, Baywide. This year, there are 48 confirmed nests throughout the Bay and 15 on the Mare Island Strait, although due to the severe early spring weather conditions, as few as 6 nests will produce chicks this season, on and near Mare Island. Osprey have not been documented to have nested in San Francisco Bay in the 20th or 21st centurie or even in more ancient times dating back to the Shellmounds of Native Indigenous people of the Bay. Public interest in and scientific monitoring of these newcomers continues to grow. Although the first successful nest on the Bay was documented on Pier 34 on Mare Island at the mouth of the Napa River in 2001, osprey nesting and in growing numbers, moving southward from Mare Island, is still a relatively new phenomenon in San Francisco Bay. Because of this significant increase and a growing interest in the story by the public, the Mare Island Heritage Trust which founded and for 13 years, managed the Mare Island Shoreline Heritage Preserve where many of the nests are located, is hosting this 11th annual event that features San Francisco Bay’s osprey phenomenon.

Bay Area webcam helps the public view osprey nesting virtually

Webcams are popular tools for public access to nesting birds. Located in Richmond sfbayospreys.org is hosted by Golden Gate Audubon Society. Its high-definition, dual camera webcam is perched above the osprey nest on the whirly crane at the Richmond CA harbor. Installed just about 6 years ago, it can be viewed 24/7.

Without access once again to the Mare Island Shoreline Heritage Preserve’s visitor center, due to the dismissal of the Preserve founding non-profit land trust, the Mare Island Heritage Trust, in September 2019, the facility is still barricaded and under lockdown by the City of Vallejo. As a result, the popular in-person lunchtime presentation given by Tony Brake, longtime Volunteer Golden Gate Raptor Observatory Bay Osprey Monitoring Project Director, will be reposted from his 2022 report on Facebook on the Mare Island Shoreline Heritage Preserve Page, Saturday, June 24 and Sunday, June 25, 11:30am-12:30pm.

His presentation is packed with info. about the nesting osprey population in San Francisco Bay which has grow and expanded Southward over the last decade, with a documented 48 active nests between Vallejo and the South Bay this 2023 season, down from 56 successful nest sites in 2022. Since almost all of the nests are on human-made structures, there have been numerous cases of nest removal and disturbance. Tony notes that “such conflicts are readily remedied by providing alternative nest platforms to divert osprey.”  This has been accomplished for about ten nests which will allow this iconic species to continue to expand and thrive in San Francisco Bay. And, Dr. Brake observes that while this has been an “approach adopted elsewhere, since Osprey nesting is new to this region, it is now needed in the Bay Area.”

Where and when to view Osprey on Mare Island in guided outings during Osprey Days and self-guided hikes and driving tours of the Preserve and Island following the event

During the Osprey Days event, various guided outings will take place June 23, 24 and 25 along the first half mile of the Mare Island Shoreline Heritage Preserve Trail leaving from the parking lot at the closed visitor center, 167 O’Hara Ct. @ the deadened of Azuar Dr and leaving from the gate entrance of the Mare Island Preserve, on Mare Island in Vallejo. Self-guided hikes can be taken in the Mare Island Preserve throughout the Osprey Days weekend, Friday, Saturday and Sunday, June 23-25, 8:00am-5:00pm. Even after the Osprey Days event, the public can continue to view osprey into late August, when the Preserve is open, every Friday through Sunday 8:00am-5:00pm using markers and directional arrows pointing to nest sites visible along the first one-half mile from the parking lot at the closed visitor center along the main paved trail. The public will see osprey nests and osprey perched and flying in the skies there into the late summer months before their migration south. Osprey fledglings are in the sky throughout the central historic shipyard including the waterfront areas near the Napa River and over Alden Park, the historic forested park with the gazebo bandstand near Officer’s Row. Osprey enthusiasts can also drive on their own near the Mare Island shipyard shoreline area where there is limited public access, to view osprey perched on cranes and other structures and soaring above the Napa River. One most northerly nest on the Island is located near the offramp to Mare Island from Hwy 37.

Osprey Days continues into the evening hours with a gathering Saturday evenings at the Mare Island Shoreline Heritage Preserve Gate area

Saturday evening, June 24, 6:00pm-8:00pm short guided walks by Myrna Hayes will be given to a nearby nest to view osprey on or near their nest. Walks begin at 6:30pm and 7:30pm from the Mare Island Shoreline Heritage Preserve gate, Correa Ct at Azuar Dr. on Mare Island in Vallejo. A light BBQ and refreshments for a requested donation will be offered. It is likely that osprey will soar and call overhead the small park area outside the closed gates of the Preserve during the evening. Osprey and other wildlife take advantage of the “hunting hour” till dusk, making it an ideal time of day to view wildlife.

Mobility challenged will be accomodated on all Osprey Days Outings

Mobility challenged individuals will be accommodated on all outings. It is advised that the public visit the event website www.mareislandpreserve.com or the Mare Island Shoreine Heritage Preserve or San Francisco Bay Osprey Days, Facebook pages for a detailed schedule. Dogs are allowed in the Mare Island Preserve on leash. Organizers assure that dogs can also be brought along on the car caravan, as long as they can be kept comfortable in or near the car. Mr. Leong does not allowed dogs, even on leash, to join the group gatherings at the car caravan stops.

History of San Francisco Bay Osprey Days’ Founding on Mare Island

“We held our first osprey day with very short notice in July 2013. In talks together with our volunteers and Tony Brake and Harv Wilson from the Golden Gate Raptor Observatory, we felt like it was really important to get an event together so that we would have a jumpstart on what we needed in place for the annual nesting season. For the second year, osprey were observed migrating from their southern range in February, even earlier than the previous March and April timeframes. We timed this year’s event at the peak of nesting and fledging activity in late June”, said Myrna Hayes, Co-founder of Osprey Days, President of the Mare Island Heritage Trust and volunteer Preserve Manager 2007-2019. “We have been seeing the numbers of nests and chicks remain stable in our Preserve where osprey are using former Navy shipbuilding cranes, now idle and abandoned lightpoles, even rooftops and other structures including the most amazing one of all, a dead palm tree, upon which to build their nests. We have learned that the nests on the dead palm tree is the only nest not on a manmade structure in the Bay. That’s pretty wild, when you think about it! It is so exciting when Preserve users return from the mile roundtrip walk and report their observations of nests with adults and young.”

“Beginning in the 2019 timeframe, as really a bonus for birdwatchers, we have 10 pairs of nesting great egrets, some just a few feet off the main trail and a number of great blue herons nesting within easy view of the trail, as well. This year, in the 2023 nesting season, volunteer citizen monitors have documented 12 great egret nests in the Mare Island Preserve. It’s all quite spectacular and very noisy!”, said, Ms. Hayes. An added bonus for bird viewing in the Preserve is the many trees close to the river for the young to perch on as they learn to fly and an abundance of lightning rods throughout the former Naval Ammunition Depot on which the Preserve is located, also used as perches by young and adult birds.

Features of the Mare Island Shoreline Heritage Preserve

In addition to nesting osprey, key features of the Preserve are spectacular scenic vistas encompassing 7 Bay Area counties, Mt. Diablo, Mt. Tamalpais and Mt. St. Helena, the Carquinez Strait and Sonoma and Napa Valleys and the U.S. Navy’s first cemetery in the Pacific, founded in 1858. The Mare Island Naval Ammunition Depot on which the Preserve is now located, was founded by the US Navy to manufacture, store, transport and dispose of munitions for the Navy’s Pacific operations, 166 years ago, in 1857. For info. Text/call 707-249-9633. Visit our website: www.mareislandpreserve.com

Please note: Tours of The Preserve are available to any reporter or photographer covering these events. Call Myrna Hayes, 707-249-9633 (cell) to schedule a tour.