Audublog

How the drought is affecting birds

February 18th, 2014 · by Garrison Frost

sandhills_sanluis_chuq

Severe drought conditions in California are having a big effect on just about everyone, including the birds. Even though we’ve finally received some rain in the last couple of weeks, we’re still a long way from where we need to be – nobody is celebrating the end of the drought. We’ve been speaking with our colleagues in the field over the last few weeks about the impact of the drought on birds, and put together the following notes based on those conversations. This is by no means a comprehensive list of impacts, but it certainly gets to some of the bigger issues:

Wetland birds at risk

California has lost a great deal of wetland habitat over the years, making the small amount of habitat that remains all the more precious. In this drought, these remaining wetlands are getting even less water than usual. The rivers and streams that feed these wetlands are dry, and government allocations of water to wetland refuges (in the Central Valley, in particular) have been cut dramatically. New legislation introduced into Congress would cut these allocations even further.

Waterfowl that rely on these wetlands as staging grounds for migration, overwintering, or breeding, are finding less habitat than they need. Some birds will fly over and try to make their migration without stopping. Those that do stop, will be forced to congregate in the limited areas where there’s water, putting them at risk of disease. We’ve seen massive die-offs resulting from this type of crowding. Moreover, food resources in these wetlands are also limited.

Agricultural habitat also limited

With natural wetlands going dry, many birds will try to make use of one of the few wet areas of the landscape: agriculture. Sadly, the crops that are getting prioritized for water (such as walnuts) most of the water aren’t the ones that are the most hospitable to birds (such as rice or alfalfa).

The other drawback of birds being forced onto farmland is the potential risks they face there. The best example of this is the Tricolored Blackbird, which we’ve been trying to encourage to make more use of natural habitat for breeding because the dairy farms the species chooses are fraught with risk. Huge colonies of the bird make their nests in the wheat, but often their chicks aren’t able to fledge before the farmer must harvest the field – resulting in huge losses.

Salinity

The great saline lakes in California’s interior (Mono Lake, Owens Lake, Salton Sea, for instance) host millions of shorebirds every spring during migration. The ecology of these places is incredibly delicate, and less water can result in a spike in salinity that eliminates the brine flies that all these birds rely on for food. The brine flies and the shrimp that feed the birds exist in a narrow window of salinity that a shortage of water can completely turn upside down.

Speaking of flies

So many songbirds rely on flies and other bugs for food. Less water in the environment means lower hatching levels for these insects. This drop in insects can result from either less standing water or a reduction in flowering trees.

If you haven’t noticed, most of our hills are still brown. Ranchers are reporting that grass isn’t growing, and there’s a real concern that we won’t see the wildflowers anywhere near normal. This could impact all those nectar-loving birds, such as hummingbirds. And less grass will be trouble for birds that commonly nest in the grass.

Long-range impacts of drought

As Audubon California’s Coastal Stewardship Director Andrea Jones pointed out: “It can take a few years to really see the impact of drought. In most cases, birds don’t just visibly die. Instead, they just don’t reproduce, and you’ll see the population levels decline for several years.”

Again, this is just a quick set of notes on the subject. We’ll continue to detail these impacts in the next weeks and months.

(photo of Sandhill Cranes dancing at the San Luis National Wildlife Refuge by Chuq Von Rospach)

Categories: Audubon California · Bird conservation · Bird Habitat · Tricolored Blackbird · Water issues

One Comment so far ↓

  • Rick Noss

    Every year I look forward to the flocks of Sandhills sailing over my home in El Dorado Hills, CA as a coming of Spring. It happened this past weekend. Am I just getting old or isn’t it earlier than normal? If so, is it draught or temperature related?