The Limpkin explosion: Like an invasive species in a changed world

When this field guide was published in 1966, it was clear from the range map that, if I wanted to see a Limpkin in the US, I had to go to Florida.

Limpkin species account from 1966 Golden Field Guide.
The Limpkin range map from this popular 1966 field guide.

Growing up as a kid birder in the 1970s, this was one of my first field guides. I did not see my first Limpkin until decades later, in 2005. At that time, this freshwater snail and mussel specialist was still largely a Florida bird, with only a scattering of records north of their usual range.

Limpkin records north of Charleston, SC up thru 2015
Extra-limital records up thru 2015 (on eBird).

Between 1956 and 2015, eBird shows only 18 Limpkin sightings north of Charleston, South Carolina, though presumably some historical records have not been entered. Suffice it to say, a Limpkin in this region was a rarity. There were no Gulf Coast records in Texas, Louisiana, Mississippi, or Alabama, and only a few in the Florida panhandle west of the Tallahassee area.

Suddenly, all this changed. 2019 saw records from Illinois, Ohio, Virginia, and coastal Louisiana, in addition to dozens of records from Alabama, Georgia, and South Carolina. 2020 and 2021 added a scattering of records from Texas to Minnesota(!) to Maryland.

Extralimital Limpkin records across the eastern US in 2022 and 2023 (so far)
The remarkable Limpkin invasion so far.

In 2022, they simply exploded, with first state records across much of the continent. 2023 looks like it is picking up where last year left off.

This kind of rapid range expansion is typically seen in invasive species who are introduced into a new ecosystem. They either die out or explode. The Limpkin invasion, however, is not because they have just arrived in Florida — they are a native species — but because the ecosystem north of Florida has been transformed by a warming climate. It is as if they have landed on a new continent. They are following food — an invasive apple snail, as well as freshwater mussels.

This kind of poleward range expansion is predicted with climate change and has already been documented in hundreds of species. See, for example, my posts here:

And these scientific papers:

  •  Amano et al. 2020. Responses of global waterbird populations to climate change vary with latitude. 10: 959-964.Chen et al. 2011. Rapid range shifts of species associated with high levels of climate warming. Science 333 (6045): 1024-1026.
  • Devictor et al 2008. Birds are tracking climate warming, but not fast enough. Proc. R. Soc. B 275, 2743–2748.
  • Hitch and Leberg. 2007. Breeding distributions of North American bird species moving north as a result of climate change. Conservation Biology 21(2): 534-9.
  • Langham et al 2015. Conservation status of North American birds in the face of future climate change. PLoS ONE 10(9): e0135350.
  • La Sorte, F.A., and F.R. Thompson III. 2007. Poleward shifts in winter ranges of North American birds. Ecology 88(7):1803–1812.
  • La Sorte FA and Jetz W. 2012.  Tracking of climatic niche boundaries under recent climate change.  J Anim Ecol. 81(4): 914-25.
  • Prince, K. and B. Zuckerberg. 2015. Climate change in our backyards: the reshuffling of North America’s winter bird communities. Global Change Biology 21(2): 572-585.
  • Stephens et al 2016. Consistent response of bird populations to climate change on two continents. Science 352(6281): 84-7.
  • Virkkala, R. and A. Lehikoinen 2014. Patterns of climate-induced density shifts of species: poleward shifts faster in northern boreal birds than in southern birds. Global Change Biology 20: 2995–3003.

[A more complete list of academic papers about birds and climate change, with highlighted abstracts, is available in the Documents section of the Birds and Climate Change Facebook group.]

Like many birds with expanding ranges, Limpkins have been slowly recovering for decades from historic habitat impacts. There are historic records (from the 1800s) from Georgia, which they did not occupy again meaningfully until 1994. Likewise, expansion into the Florida panhandle was not until the late 1980s. This fits the typical climate change pattern, with ecosystem changes beginning in the mid to late 1980s. Range expansions, however, can be variable, with different species crossing ecological and climatological thresholds at different times.

eBird status map for Limpkin
The current eBird status map for Limpkins shows them as regular from Houston to North Carolina.

Like most of the species shifting their ranges, Limpkins are generally non-migratory, though may have some seasonal movements based on water levels and foraging conditions. Most the recent northern records have been in summer. It is not known if these birds return south in fall, or die, not being able to withstand the winter. That said, they are undoubtedly establishing year-round presence in southern Louisiana (where the first state record was in 2018), and likely from Texas to South Carolina. There are recent winter records from Iowa, Ohio, Oklahoma, Kentucky, and Virginia.

Limpkin southward expansion in Argentina and Chile
The Limpkin may be one of the few species expanding poleward in both directions.

The Limpkin also ranges south into Central and South America. Its scientific name is Aramus guaranauna, the latter part being the Tupí name for it. Until 2018, it did not occur south of Bahia Blanca, Argentina (at least not in eBird). Its core range ended closer to Buenos Aires. However, with a record in 2018 and four more in 2020 (based on eBird, which is used less in South America), it has spread up to 700 miles south, mimicking its poleward spread in North America. Northern Ohio is also about 700 miles from the Limpkin’s core range in Florida. The southernmost record, found dead at Puerto Deseado, Argentina, is at 47.8 degrees south latitude. The northernmost record, just north of Minneapolis, is at 45.2 north latitude. Like a true invasive species, one even crossed the Andes!

Limpkins are not the only waterbird associated with Southeast wetlands that are expanding north. Birders have noticed northward range expansions among the following:

  • White Ibis
  • Neotropic Cormorant
  • Black-bellied Whistling Duck
  • Purple Gallinule
  • Anhinga
  • Roseate Spoonbill
  • and even Snail Kite, Swallow-tailed Kite, and Mississippi Kite
Limpkin

Many of these are actually declining in Florida (or Louisiana) as they increase in the north.

Indigenous Americans relied on observations of nature to provide information about weather, or when certain plants could be planted or harvested, or when certain fish or game were available. An Anhinga in New York, a Purple Gallinule in Ohio, White Ibises nesting in New Jersey, all of which have happened in this year – would be portents of change – or doom.

Miners kept canaries in coal mines to monitor the atmosphere. A sick or dead canary meant dangerous conditions in the mine. But imagine their surprise if their mine was suddenly invaded by a hundred canaries. That would mean something was amiss outside. Limpkins are becoming those canaries.

BREAKING: One day after posting this, a first record for Ontario, Canada.

UPDATE IN JULY 2023: Limpkin has reached Pennsylvania.

A Nazca Booby, a tug, a barge, and a pit: A climate parable

At 9:30am on August 17, that is, yesterday, I got a text from another birder. A Nazca Booby had just been seen from Discovery Point near Seattle. What’s more, we knew exactly where the bird was now; it was perched on the bow of a barge being pulled by the tug Seaspan Raider.

The Nazca Booby, atop the barge, photographed by Matt Stolmeier, captain for Outer Island Excursions.

The Nazca Booby is a tropical seabird that breeds exclusively on the Galapagos Islands. When not nesting, it occurs at sea in the eastern Pacific, generally between central Mexico and northern Peru.

Breeding (orange) and non-breeding (blue) range of the Nazca Booby.

This was Washington’s third record. The first, quite possibly the same bird, was on August 14, 2020, in pretty much the same part of Puget Sound. The second was a few weeks ago also off Seattle. That one was an immature, not an adult, so we know it was a different individual. It then showed up off Victoria, providing Canada with its third record.

The Nazca Booby first arrived in the United States in California in 2013. I actually played a role in that first record, a dead beachcast bird found in the aftermath of an oil spill. Working for the state’s spill response, I brought it to the attention of the California Bird Records Committee and had experts examine the carcass for identification. That bird was not a one-off event; it was the beginning of an invasion. There were a few scattered records in the following years, followed by an explosion of 26 records in 2018 and 21 in 2019. After that, California removed the species from its “review list”. While some of these records may have been the same individuals, it is remarkable that a tropical bird previously unheard-of in the US was suddenly widespread. Oregon got its first two records in 2018 and 2019.

Sea surface temperature (SST) of 66.1F off the Washington/Oregon coast.

Checking sea surface temperatures, I see that the water off the Washington and Oregon coasts is reaching 66F in places, only 4F cooler than on the south side of the Galapagos. Zooming out, it is easy to see a route from there to here where the bird never had to encounter sea surface temps under 60F. The Strait of Juan de Fuca is in the low 50s, but it does approach 60F near Seattle.

I opened the MarineTraffic app and quickly located the Seaspan Raider. It was southwest of Edmunds, northbound at 7.3 knots. I calculated it would arrive off Port Townsend between 1 and 2pm. Birders scrambled, heading to various coastal promontories on both sides of Puget Sound. I headed to Point Wilson, where Puget Sound effectively ends and meets the Strait of Juan de Fuca. The tug, bound for Canada, would have to pass by me here.

Reports came in. The bird had flown off the barge. It was in the water off Edmunds. It took off. It was seen from both sides. No one knew where it was.

Tracking the tug using the MarineTraffic app.

This wasn’t the only booby in the Salish Sea at the moment. A Brown Booby had been photographed a few days earlier near the San Juans. That was yet another tropical seabird that had already invaded the US, with records from over forty states, including Alaska. Two decades ago, this would have been unimaginable. And this summer, 2022, was already noteworthy across the Midwest and East Coast for the mass invasion of waterbirds typically found only in Florida or the Gulf Coast. Limpkins, Wood Storks, White Ibis, Roseate Spoonbills and many others were showing up hundreds of miles north of their previously known ranges.

Scrolling thru the American Birding Association Rare Bird Alert nationwide posts, limited to just mega-rarities, here is what pops up: Brown Booby in Oklahoma, Neotropic Cormorant in North Carolina, Brown Booby in Wisconsin, two Swallow-tailed Kites in Ohio, Limpkin in Wisconsin, Neotropic Cormorant in Michigan, White Ibis in New York, Wood Stork in Pennsylvania, Heermann’s Gull in Alaska, Limpkin in Illinois, Nazca Booby in California, White Ibis in Nebraska, etc. And that doesn’t even get us back to August 1. These are all birds, mostly aquatic birds, well north of their normal ranges.

Our current rate of climate warming hasn’t been seen since the Paleocene-Eocene Thermal Maximum (PETM) 55 million years ago. Then, there were alligators within the Arctic Circle. Kind of like Nazca Boobies are now a thing in Puget Sound. Actually, our current rate of warming is much faster than then. During the PETM, the climate warmed 5C in five thousand years. The current rate of warming is eighteen times faster. Then, no one would have noticed. Now, there is 1C of warming – and, with it, dramatic changes in climate and ecology – within the lifespan of a single bird. Some seabirds are showing us that they can keep up, thanks to their ability to fly long distances. I’m not sure about the alligators. Or birds that depend, say, on oak trees. The birds can fly, but the oaks can’t.

Two hours passed. I was ready to give up and head home, my only consolation being “MAMU CF”, a Marbled Murrelet making a provisioning flight across the Sound, carrying a fish to its single chick somewhere on a moss-covered Doug fir branch a hundred feet above the forest floor, probably in the Olympic Mountains. I’d only seen that once before. Much of their range in California has been lost to fires in the past five years, so this Olympic chick is important.

The original photo of the Nazca Booby on the barge, by Alex Meilleur.

One birder, who was unable to search for the Nazca Booby, called some of the local orca boats, as he worked on some of them. He let them know about the bird, as some were near it. About twenty minutes later, texts came in. They had re-found it! It was back on the same barge, now approaching Marrowstone Point. I spun my scope south. There, beyond the ferry lane, I could make out the red and white structure of the Seaspan Raider, pulling its barge, all blurry and shimmering in the distant heat mirage, slowly chugging toward me.

Taking advantage of the outgoing tide, the Seaspan Raider was now hitting 9 knots. It is powered by two Niigata 6m G25HX diesel engines. I don’t know what kind of gas mileage it gets, but, because it presumably refueled in Washington, most of its fuel is likely conventional diesel, but a small component may be renewable diesel.

Renewable diesel is not the same as biodiesel. Biodiesel can be mixed with conventional diesel, but only in very small amounts, like 2%. Renewable diesel, on the other hand, is molecularly identical to conventional diesel. It’s a relatively new invention. Made from non-petroleum sources, such as plant and animal material, it is to conventional diesel what corn syrup is to sugar; it is a “drop-in ready” alternative fuel. It can be mixed with or substituted for conventional diesel seamlessly, with no change in gas pumps, pipelines, or engines. In fact, it burns slightly cleaner, so engines last longer. It emits fewer particulates and, most importantly, its greenhouse gas footprint is up to 80% less. Its use is already widespread in California, where two of the state’s largest refineries no longer take petroleum crude.

This is the kind of thing that should have been developed thirty years ago, just after James Hansen of NOAA briefed congress on climate change in 1986. Now it’s late. We’ve already had more than 1C of climate warming, with more coming and probably ten feet of sea level rise built into the system. Stopping carbon emissions is no longer a suitable goal. We’ve already pushed the cart down the ramp. It’s rolling. We need to reverse climate change, to change that ramp so the cart rolls back to where it was. That will require actually sucking CO2 out of the air – negative emissions – which will certainly take a hundred years under the most optimistic scenarios. So get ready for more boobies, maybe even Limpkins and alligators.

Aside about Washington: Washington further delayed action a few years ago when the Department of Ecology required an Environmental Impact Statement from Phillips 66 to convert their refinery at Cherry Point to make renewable diesel. That is to say, Phillips needed to jump through major permitting hurdles because they were changing – that is, reducing — their greenhouse gas emissions. Phillips didn’t want to wait the several years required for this, so they promptly moved their operation to California. Governor Inslee tried to intervene and save the project, but it was too late. Now BP is picking up the baton in Washington.

Renewable diesel is already in widespread use in trucks, especially in California. The ferries in San Francisco Bay are powered exclusively by it. Because diesel is similar to jet fuel, and made during the same refining process, refineries also produce what is called sustainable aviation fuel (SAF). Aircraft are currently permitted to fly with up to a 50/50 blend of SAF and conventional jet fuel. Boeing promises jets that can fly with 100% SAF by 2030. We’ll be approaching 1.5C of warming by then. Nazca Booby will almost certainly be off the rare bird review list, at least in California. Brown Boobies will be breeding on the Farallones and prospecting further north.

I watched as orca boats came and went from the barge, photographing the Nazca Booby. I was told it was on the starboard side of the roof of the little structure on the bow. The tug and barge continued up Admiralty Inlet until it was straight out from me, as close as it would pass. Slightly more than halfway across the channel, it remained blurred in heat mirage. I could see fuzzy white dots on the described rooftop, but I couldn’t tell you if they were Nazca Boobies or gulls or volleyballs. In birder’s lingo, this was going to be a ‘dip’, even though I knew exactly where the bird was and was looking at it.

My view of the tug, barge, and bird.

Mathematically, this would be at least the sixth time a Nazca Booby had passed this point, my point, my sea watch. And this time I was here, ready and waiting, and still I couldn’t see it. Were it not for the texts and the orca boats, I’d never know it was there. I kept my scope glued to it, hoping it would lift off in a distinctive flight and head directly toward me, where it would join the Caspian Terns and plunge dive right in front of me as I clicked my camera in ecstasy. But it didn’t. The tug and barge chugged north.

The bird was last seen at Partridge Point on Whidbey Island, still riding the barge. It was off the barge by Rosario Inlet. I’m guessing it jumped ship and headed toward Victoria or Smith Island.

The barge’s destination was the Lafarge Texada Quarrying Ltd. limestone mine north of Vancouver. Limestone is critical to making cement. The cement-making process is responsible for 8% of the world’s carbon emissions. Part of that is from the energy used in production, which requires a kiln heated to 1,400 degrees Celsius. But most of the emissions comes from the limestone itself. Forty percent of the weight of limestone is CO2, and this is burned off in the process. There are efforts to improve the cement-making process, to make it less dependent on limestone, to reduce its carbon emissions. That’s all coming in the future.

The limestone mine at Beale Cove, the barge’s destination.

I’m wondering about the ancient Nazca civilization in what is now Peru. It was dependent on a remarkable network of underground aqueducts that delivered mountain water to their arid home. There’s a theory that they over-harvested a certain tree, which led to erosion of riversides during heavy rains, destroying their water delivery system. I wonder if they had meetings about the problem, if they had new policies in effect, at least at the end, when it was too late.

It’s supposed to be 95F in the Seattle suburbs today. I’m not worried about missing this Nazca Booby. There will be more.

The Nazca Booby on the bow. I’m sure the scope views were better. Photo by Laura Brou.

The invasion of the Pacific Northwest: California’s birds expand north with warmer winters

Birds, because of their mobility, are considered to be fairly adaptable to climate change. They evolved in the aftermath of two of the world’s most catastrophic warming events (the K-T extinction and the Paleocene-Eocene Thermal Maximum), spreading to the Arctic, crossing continents, and evolving along the way. While those warming events took place over tens of thousands of years, the current warming is happening in the space of a couple hundred, with noticeable changes in climate within the lifespan of a single bird.

There will be winners and losers. Generalists, and species that enjoy warmer weather, are likely to be winners. Those with narrow food or habitat requirements, especially those dependent on the ocean or the Arctic/Antarctic, will likely be losers. Although counter-intuitive, it is primarily non-migratory resident species that seem to be more adaptable to a changing climate.

Recent studies

Studies of climate impacts on western North American birds using past data are limited, but some focusing on California were recently published. Iknayan and Beissinger (2018) showed that, over the last 50 years, “bird communities in the Mojave Desert have collapsed to a new, lower baseline” due to climate change, with significant declines in 39 species. Only Common Raven has increased. Furnas (2020) examined data from northern California’s mountains, showing that some species have shifted their breeding areas upslope in recent years. Hampton (myself) (2020) showed increases in many insectivores, both residents and migrants (from House Wrens to Western Tanagers), in winter in part of the Sacramento Valley over the last 45 years. These changes, particularly range shifting north and out of Southwest deserts, is predicted for a wide number of species.

The invasion of the Pacific Northwest

Here I use Christmas Bird Count (CBC) data to illustrate that some of California’s most common resident birds have expanded their ranges hundreds of miles north into Oregon, Washington, and British Columbia in recent years. The increases are dramatic, highly correlated with each other across a wide range of species, and coincide with rapid climate change. They illustrate the ability of some species to respond in real time.

In parts of Oregon and Washington, it is now not unusual to encounter Great Egret, Turkey Vulture, Red-shouldered Hawk, Anna’s Hummingbird, Black Phoebe, and California Scrub-Jay on a single morning—in winter. A few decades ago, this would have been unimaginable. Some short-distance migrants, such as Townsend’s Warbler, are also spending the winter in the Pacific Northwest in larger numbers.

The following graphs, showing the total number of individuals of each species seen on all CBCs in Oregon, Washington, British Columbia, and (in one case) Alaska, illustrate the range expansions. Adjusting for party hours scarcely changes the graphs; thus, actual numbers of individuals are shown to better illustrate the degree of change. The graphs are accompanied by maps showing predicted range expansions by the National Audubon Society, and recent winter observations (Dec-Feb) from eBird for 2015-2020.

These range expansions were predicted, though in some cases the recent trends exceed even projected scenarios under 3.0C increases in temperature.

Let’s begin with the climate. Canada as a whole has experienced 3.0C in temperature increases in winter. British Columbia has experienced an average of 3.7C increase in Dec-Feb temperatures since 1948. The greatest increases have been in the far north; increases in southern British Columbia, Washington and Oregon have been closer to 1.5C.

winter temps in Canada.jpg

Average nationwide winter temperatures deviation from average.

Great Egret

Great Egrets on Oregon CBCs have increased from near zero to nearly 900 on the 119th count (December 2018 – January 2019).

CLICK ON GRAPHS TO ENLARGE

GREG OR graph.jpg

But their expansion, which took off in the early 1990s into Oregon, is now continuing in Washington, with a significant rise beginning in the mid-2000s. Great Egrets occur regularly in southern British Columbia, but so far have eluded all CBCs.

GREG WA graph.jpg

They have not quite fulfilled the full range predicted for a 1.5C increase, but are quickly on their way there.

GREG maps.jpg

Turkey Vulture

Turkey Vultures began increasing dramatically in winter in the Sacramento Valley of California in the mid-1980s, correlated with warmer winters and a decrease in fog. Prior to that, they were absent. Now, over 300 are counted on some CBCs. That pattern has been repeated in the Pacific Northwest, though about 20 years later. Both Oregon and British Columbia can now expect 100 Turkey Vultures on their CBCs. Curiously, Puget Sound is apparently still too cloudy for them, who prefer clear skies for soaring, though small numbers are regular in winter on the Columbia Plateau.

TUVU CBC graph.jpg

TUVU maps.jpg

Red-shouldered Hawk

Red-shouldered Hawks have increased from zero to over 250 inviduals on Oregon CBCs, taking off in the mid-1990s.

RSHA OR graph.jpgTwenty years later, they began their surge into Washington. It’s a matter of time before the first one is recorded on a British Columbia CBC.

RSHA WA graph.jpg

While their expansion in western Washington is less than predicted, their expansion on the east slope, in both Oregon and Washington, is greater than predicted. This latter unanticipated expansion into the drier, colder regions of the Columbia Plateau is occurring with several species.

RSHA maps.jpg

Anna’s Hummingbird

If this invasion has a poster child, it’s the Anna’s Hummingbird, which, in the last 20 years, have become a common feature of the winter birdlife of the Pacific Northwest. Their numbers are still increasing. While much has been written about their affiliation to human habitation with hummingbird feeders and flowering ornamentals, the timing of their expansion is consistent with climate change and shows no sign of abating. Anna’s Hummingbirds are not expanding similarly in the southern portions of their range. The sudden rate of expansion, which is evidenced in most of the species shown here, exceeds the temperature increases, suggesting thresholds are being crossed and new opportunities rapidly filled.

ANHU CBC graph.jpg

The expansion of the Anna’s Hummingbird has now reached Alaska, where they can be found reliably in winter in ever-increasing numbers.

ANHU AK graph.jpg

The range expansion of the Anna’s Hummingbird has vastly outpaced even predictions under 3.0C. In addition to extensive inland spread into central Oregon and eastern Washington, they now occur across the Gulf of Alaska to Kodiak Island in winter.

ANHU maps.jpg

Black Phoebe 

Non-migratory insectivores seem to be among the most prevalent species pushing north with warmer winters. The Black Phoebe fits that description perfectly. Oregon has seen an increase from zero to over 500 individuals on their CBCs.

BLPH OR graph.jpg

With the same 20-year lag of the Red-shouldered Hawk, the Black Phoebe began its invasion of Washington.

BLPH WA graph.jpg

The figure below illustrates two different climate change predictions, using 1.5C and 3.0C warming scenarios. While nearly a third of the Pacific Northwest’s Black Phoebes are in a few locations in southwest Oregon, they are increasingly populating the areas predicted under the 3.0C scenario.

BLPH maps.jpg

Townsend’s Warbler

Migrant species tend not to show the dramatic range expansions of more resident species – and short-distance migrants show more range changes than do long-distance migrants. Townsend’s Warblers, which winter in large numbers in southern Mexico and Central America, also winter along the California coast. Increasingly, they are over-wintering in Oregon and, to a lesser degree, Washington. This mirrors evidence from northern California, where House Wren, Cassin’s Vireo, and Western Tanager are over-wintering in increasing numbers. These may be next for Oregon.

TOWA WA OR graph.jpg

Townsend’s Warblers are already filling much of the map under the 1.5C warming scenario, though their numbers on CBCs in Washington and British Columbia have yet to take off.

TOWA maps.jpg

California Scrub-Jay

Due to problems with CBC data-availability, I have no graph for the California Scrub-Jay. Their northward expansion is similar to many of the species above. Their numbers on Washington CBCs have increased from less than 100 in 1998 to 1,125 on the 2018-19 count. eBird data shows they have filled the range predicted under the 3.0C scenario and then some, expanding into eastern Oregon, the Columbia Plateau, and even Idaho.

CASJ maps.jpg

Other species

Other species which can be expected to follow these trends include Northern Mockingbird and Lesser Goldfinch. (See more on the expansion of the Lesser Goldfinch here.) White-tailed Kite showed a marked increased in the mid-1990s before retracting, which seems to be part of a range-wide decline in the past two decades, perhaps related to other factors.

Curiously, three of the Northwest’s most common resident insectivores, Hutton’s Vireo, Bushtit, and Bewick’s Wren, already established in much of the range shown on the maps above, show little sign of northward expansion or increase within these ranges. The wren is moving up the Okanogan River, and the vireo just began making forays onto the Columbia Plateau. Both of these expansions are predicted.

Likewise, some of California’s oak-dependent species, which would otherwise meet the criteria of resident insectivores (e.g. Oak Titmouse), show little sign of expansion. Oaks are slow-growing trees, which probably limits their ability to move north quickly. Similarly, the Wrentit remains constrained by a barrier it cannot cross—the Columbia River.

Call it the invasion of the Northwest. Call it Californication. Call it climate change or global warming. Regardless, the birds of California are moving north, as predicted and, in some cases, more dramatically than predicted.

ANHU CBC graph.jpg