Editorial: Marin shorebirds help track health of coastal ecosystem

Bird populations are an indication of the health and vibrancy of the local ecosystem. A recent report shows a steady decline in Bay Area shorebird numbers.

A program leader at Point Blue Conservation Science, one of the authors of the report, says the numbers show an “alarming drop” from those counted in a similar 2011 study.

The bird population can be sort of like the proverbial “canary in the coal mine,” an indicator of the health of its local ecosystem.

The new count can also be an indicator of local and regional weather patterns and land-management practices.

Sometimes, California’s numbers can fluctuate depending on local activities, such as when and how farmers decide to work their fields or other human activities along their long migration routes.

Often, those who pay attention to birds will notice year-to-year changes in the numbers among different species.

Many local shorebirds make those migrations, typically stopping in the Bay Area every winter to feed and rest up for their flight north.

Given the expanse that they travel and numerous factors, there are likely a lot of reasons for the population decline. Other areas along the way may provide better habitat or less attractive habitat causing the birds to alter their pattern.

That doesn’t mean we shouldn’t pay heed to marked downturns in numbers, especially since efforts to protect, recover and restore the bay’s wetlands have increased over the last 50 years.

Many of those efforts have reversed decades of losing baylands for the development of subdivisions, officeparks, shopping centers, airports and other human uses.

That should provide good reason for a steady upswing in populations.

The numbers in the study commissioned by the San Francisco Bay Joint Venture and Point Blue are well worth monitoring.

The steepest decline in the North Bay documented in the report – “San Francisco Bay State of the Birds” – were among medium-size shorebirds, such as dowitchers and black-bellied plovers.

American avocets, marbled godwits, willets are other larger shorebirds that also saw a decline over the past 20 years.

Smaller birds – sandpipers and dunlins – were also counted in lesser numbers, but not as steep. The report, however, also showed a 6% regionwide decline in the Ridgway’s rail, an endangered federally protected bird that makes its home in tidal marshes.

Meanwhile the report indicated an overall increase in birds dependent on tidal marshes, such as song sparrows, common yellowthroats and rails.

The report says the results may be a sign of the ecological success of North Bay efforts to preserve and restore baylands, including transformation of the former Hamilton airfield into a 648-acre tidal and seasonal wetland.

The area has become one of the Bay Area’s most popular birding spots.

It supports more than 100 species of birds and is a good example of the importance of our baylands to the bay’s ecosystem.

Popular support for such an environmental initiative was underscored in 2016 when Bay Area voters approved a special nine-county parcel tax for tidelands protection and restoration and flood control. The tax measure was approved with a majority vote of 70%. In Marin, that support was even greater.

But the recent bird counts should not go unnoticed or unheeded.

It is unlikely follow-up reports will benefit from federal funding given the current administration’s disinterest in supporting California’s agendas and its weak track record of environmental protection.

They are living reasons why the successes we have had in protecting and enhancing our region’s wetlands are so important and deserve to remain a top priority.

The report shows the importance of clean water and healthy habitat.

As a primary sign of the health of our bay’s estuarine habitats, the state of our bird populations are vitally important. Further monitoring is important to learn more about the striking variations detailed in the latest report.