Winter Days at the National Wildlife Refuges of the Great Valley, and Remembering What Once Was

Cross-posted from Geotripper (it's about California birds after all)  What's the largest number of birds you've ever seen from one spot?

The Great Valley of California is a great place to see a lot of birds in one place. In pre-colonist days, the 400-mile-long valley was a prairie that was watered by a series of rivers flowing from the adjacent Sierra Nevada. There was enough water that even in historical time there were two immense lakes between Bakersfield and Fresno, Tulare Lake and Buena Vista Lake. Before water diversions for irrigation caused it to dry up, Tulare Lake was the largest freshwater lake west of the Mississippi.

Source: Quora

The mild winter climate of California led to the adoption of the wetlands and marshes of the Great Valley as the favored seasonal home of millions upon millions of waterfowl and other migratory birds of the arctic and far north. I can hardly begin to imagine what a wintertime journey through the pre-European Great Valley must have been like.

The ecological role of grazer in the refuges is occupied by a handful of deer and lots of sheep and cows to make up for the now-extinct megafauna

But historical accounts and paleontology can provide us some idea. In addition to birds, the vast prairies supported huge herds of tule elk, deer, antelope, and even bison. Prior to 12,000 years ago, the plant-consuming animals included giant ground sloths, mammoths, mastodons, horses, and camels. The birds and grazing animals were the prey of an imposing array of predators including the recently departed California Grizzly Bear, black bears, wolves, mountain lions, coyotes, and foxes. The pre-12,000-year crew included saber-toothed cats, dire wolves (bigger than wolves of today), American Lions, jaguars, and the immense Short-faced Bear, an animal that would have made a Grizzly think twice about a confrontation. The reason for the almost simultaneous extinctions of the species of the so-called 'mega-fauna' is a subject of contention among geologists, paleontologists and anthropologists (the role of humans has not been ruled out).

This cuddly little Short-faced Bear can be seen at the Fossil Discovery Center near Madera

I was thinking about this as we made our customary winter journeys to the local national wildlife refuges in and around Modesto and Merced. The main units open to visitation include the Merced, the San Luis (including the separate Bear Creek Unit), and the San Joaquin River National Wildlife Refuges. Although the boundaries of these refuges tend to be very square or rectangular and they are crisscrossed by maintenance roads, they are the only places that come close to recreating the primeval landscape that once existed.

The national wildlife refuge system grew out of a number of motives, some noble, others not so much. When wetlands of the valley were drained and planted with crops, millions of birds found their ancestral winter homes gone. With nowhere else to go, many of the geese and others began to forage on the tilled fields to the distress of the farmers. Instead of massacring untold numbers of birds, a series of refuges were established up and down the valley to provide a haven and food for at least some of the migrants. Of course, the refuges were also designed to preserve populations of the birds so they could be shot. Much of the refuge funding comes from the sales of hunting permits.

Snow Geese at the San Luis National Wildlife Refuge

So that is where are today. The refuges provide forage for millions of migratory cranes, geese, swans and ducks (in many they grow fields of corn for the singular purpose of feeding the birds). The birds are too crowded, and diseases can spread if the flocks are not managed properly, but it is a better situation than having no refuges at all. Some species, especially the Aleutian Cackling Goose, have been brought back from the brink of extinction (once down to just 300 or so birds, the population is more than 100,000; they mostly shelter at the San Joaquin NWR just west of Modesto). And yearly, more and more abandoned farmlands are being converted to the original riparian habitat to allow for population growth. 

I don't do video often, but the one at the top seemed necessary because I was looking at what I believed was the largest single grouping of birds I've ever seen (and I've been exploring these refuges for 7-8 years now). It required about a 180-degree pan. On the other hand, there is nothing in the world quite like watching thousands of geese taking flight all at once. When we were at the San Luis NWR last week, the serene view was of several thousand Snow Geese and Tundra Swans. It's not really a good thing for the birds to be scared into the air, as it uses precious energy, and they could get hurt. But a helicopter flew overhead at a low elevation, and it spooked the geese (the swans seemed like they could care less) and several thousand took flight. I caught the flight on video, and you can clearly hear the helicopter. I took a picture of the craft thinking to report it, but it turned out to be medi-flight out on an emergency call.  

The number of birds and the variety of birds at the local refuges is truly astounding. We saw 50 species at the San Luis Refuge last week and 46 at the Merced Refuge yesterday. The really good birders will report 60-65 in a single trip. And the birds are beautiful. Here are some that caught my eye this last week.

This Great Egret was at the San Luis NWR. Both refuges offer "auto-tours" where visitors stay in their cars (kind of like those African savannah tours, but there aren't any lions trying to eat you). The cars serve as blinds, startling birds far less than humans bumbling around.

We were looking for swans and saw large white birds off in the distance. They turned out to be American White Pelicans. They may be the most ungainly-looking birds on the ground but are positively graceful in flight. And they are huge.

The blue bill of the Ruddy Duck is rather distinctive.

The prize for wildest beak goes to the Long-billed Curlew. I guess they can reach bugs and worms in the mud and soil that other birds can only dream of.

The Greater White-fronted Goose may be one of the more unfamiliar goose species around the valley. I've seen only a few in urban settings. Like the others, they are long-range migrants.

One of the special treats for the last two or three years has been a female Vermilion Flycatcher that decided to spend winters at the Merced NWR. This is the extreme north end of their range, and only a few are ever seen on a yearly basis in Stanislaus or Merced counties. Global warming may be allowing them to expand northward, and it may be only a matter of time before the scattered males and females find each other and start making little flycatchers.

This is an American Avocet, another bird that has a crazy bill that is good for probing deep in the mud.

There are a goodly number of raptor species that live in the refuges. One of the most beautiful is the White-tailed Kite. We thought we were done with photo opportunities when we reached the open grasslands at the end of the auto-tour at Merced, but this kite was perched on the sole tree eyeing the ground squirrels (and they were eyeing it).

The last bird of the day was the biggest surprise of all because it was the first time I had seen it in several years. It's a Black-bellied Plover, and it's not all that rare. It's just that I don't always know to look for it or recognize it when I see it. And it doesn't have a black belly. The males grow it when breeding season comes along.

Sunset at the Merced NWR

We here in the Great Valley sometimes forget that it is indeed a great valley, and that there are treasures that lie just beyond the boundaries of our cities. The auto-tours at Merced and San Luis provide opportunities for all, but those who want to walk will find a number of nice level trails. I especially recommend the Pelican Trail at the San Joaquin River National Wildlife Refuge. It passes through a series of diverse habitats and offers the greatest diversity of birds outside of the Modesto Water Treatment Plant (seriously, sewage ponds attract a lot of birds!). Check it out sometime, or any of the others up and down the valley.

Thousands of Aleutian Cackling Geese at the San Joaquin NWR. They were thought to be extinct for 24 years.

This is a reposting of a column at Geotripper

I live in California's Great Valley, also known as the Central Valley. It's one of the most important agricultural regions on Earth, in that it produces around a quarter of the nation's produce. It's an extraordinary geological province, 400 miles of almost perfect flatness. When I moved to the valley nearly thirty years ago, I thought I was moving to a boring place, featureless, and bereft of the kinds of terrain that makes a geologist's heart go pit-a-pat. I was wrong...

I must admit that an exploration of the valley can be a bit monotonous. Traveling Highway 99 or Interstate 5 involves hundreds of miles of featureless fields and orchards, interrupted now and then by towns whose cultural attractions consist of gas stations and fast food restaurants (don't get me wrong, some of our towns have fascinating cultures, but you may have to work to find them at times).

The valley environment ranges from oak woodlands in the north through semiarid prairie in the middle reaches to barren desert to the south. The land is actually well-watered, as the adjacent Sierra Nevada feeds numerous rivers that flow into the valley. The rivers have been mostly diverted for use in irrigation, but about 30% of the water continues on to the sea. About 95% of the land surface in the valley has been converted to agricultural and urban development.

What has enriched my life in recent years is seeing the valley the way our migrant birds see it: a series of "wilderness" islands that allow me to imagine the valley as it once was, America's version of the Serengeti Plains. The prairies and wetlands once supported millions of grazing animals and migrating bird species (along with the year-round resident species). Most of these "islands" are part of the National Wildlife Refuge system, while others are preserves administered by a variety of federal, state and private organizations. These refuges allow the preservation and survival of the remnants of the incredible ecosystem that once existed here. It took a long time to recognize what we were doing to these animals as we took away more and more of their habitat to grow our food, but now there is a movement towards rehabilitating some of the wetland environments. We are trying to undo the damage we've caused over the last century and a half.

I was reminded of these efforts this afternoon when I drove over to a viewing area at the San Joaquin National Wildlife Refuge, one of the main centers of the efforts to rebuild the wetlands (something like 400,000 trees have been planted in riparian habitats that had been converted to farmlands, later abandoned). I saw an astounding sight.

There were perhaps tens of thousands of Aleutian Cackling Geese (Branta hutchinsii leucopareia) gathered in a plowed cornfield (planted by the refuge employees to provide food for the birds). The birds are closely related to the Canada Goose, but are considered a separate species based on DNA analysis. The species had gone into a steep decline due to hunting, the introduction of foxes on the island where they bred, and loss of winter habitat in the Central Valley. They were actually thought to be extinct for twenty four years, as none were seen after 1938, but a group of several hundred were found on some isolated islands in 1962. They were listed officially as an endangered species in 1967.

Aggressive efforts began to protect the birds from extinction, and in fifty years, the results have been successful enough that the bird has been removed from endangered status. From a population of less than 1,000 birds, there are now more than 120,000. And I was looking at a large percentage of the entire population of these birds at the San Joaquin National Wildlife Refuge this afternoon. It was stunning.

The birds certainly still face problems. They are crowded onto relatively limited lands, and drought years can limit the amount of maize and wheat that can be planted on their behalf. The drought also limits that available wetlands that they prefer for roosting. But still for a few moments this afternoon, I was reminded how the valley used to support millions of geese and cranes. It may still do so again. It's possible to share the bounty of our valley with the original inhabitants.

I imagine some people would think I was exaggerating a bit when I said there were thousands, maybe tens of thousands of birds at the refuge this afternoon. I certainly couldn't fit them all into a single picture, so I invite you to see a video I took, sweeping across the crowd next to the road. Enjoy!


More on the recovery of the Aleutian Cackling Goose can be read here: http://www2.humboldt.edu/wildlife/faculty/black/pdf/Minietal2011_AleutiansWildfowl.pdf