As the World Heats Up, Can Ceramic Nests Help Birds Stay Safe and Cool?

For most of us, a 75-degree day doesn’t present much occasion to complain about the weather. A Cassin’s Auklet, though, might beg to differ; nesting along the Pacific coast predominantly between Alaska and British Columbia, the small, chunky seabirds like to keep it cool.  

For decades, a colony of about 30,000 auklets has found the conditions at the Farallon Islands National Wildlife Refuge, a craggy archipelago 30 miles west of San Francisco, chilly and breezy enough to stick around. But in 2008, when thermometers on Southeast Farallon Island cracked 75 for one of the first times since a late '90s heat wave, researchers from Point Blue Conservation Science got worried. Reaching inside the wooden boxes the team provides many of the auklets for nesting, they found the birds were suffering from heat stress and exhaustion. And worse, they weren’t doing anything about it. 

On a hot day, in direct sunlight, the auklets’ little boxes can become tiny ovens, reaching over 100 degrees, says Pete Warzybok, a marine ecologist at Point Blue. Even so, when the auklets are incubating an egg or brooding a chick, “they’re just going to sit there engrossed all day long. They don’t have the incentive to leave.” Warzybok and his colleagues scooped their tiny charges out of the boxes and dunked them in the ocean to help them cool off.  

That solution worked as a quick fix. But on the Farallones, the number of extreme heat events—days where the midday temperature breaks 68 degrees Fahrenheit—is climbing. And it’s not just the Bay Area: Across the world, record-breaking temperatures are stressing bird species of all stripes. It’s a particular challenge for populations that rely on nest boxes or other kinds of artificial enclosures, whether for scientific observation, fostering population growth, or because their natural habitats have become untenable for nesting. The containers, predominantly made from wood or composites, aren’t often designed to control temperature, and can end up overheating more quickly than homes of birds’ own making. Many artificial nests are also vulnerable to damage from time and larger animals.

That’s brought a new material into the conversation, one perhaps more familiar to art than science: clay. After Point Blue’s scientists tested domiciles made of a range of materials, they found ceramics had a unique ability to keep temperatures moderate on the most dangerous days. Today, they’ve added almost 90 sleek, spaceship-like units to the auklet housing market on the Farallones, with 25 more on the way next year. Similar clay nests are starting to take shape from Hawaii to South Africa, and conservationists are recognizing their potential as a simple solution to help birds survive as their habitats heat up.

The nests on the Farallones are part of an ongoing partnership that bridges biology and craftsmanship. When Michelle Hester, the executive director of the conservation nonprofit Oikonos: Ecosystem Knowledge, noticed more rotting and damaged wooden boxes needed replacements in seabird sites across the Pacific, she felt an inkling clay might be worth exploring: It’s a natural material with few limits on its creative potential. She enlisted the help of San Francisco sculptor Nathan Lynch to create some new avian digs, who in turn brought on students from the California College for the Arts to help brainstorm techniques for “bird-centered design.” 

Their first tenants were the Rhinoceros Auklets of Año Nuevo Island, north of Santa Cruz, whose underground burrows were collapsing due to wind erosion and getting trampled by neighboring sea lions. In 2010, Lynch and Oikonos installed around 90 of their clay substitutes, and soon saw success as the auklets began breeding chicks inside the modules. Since then, the partners have brokered homes for seabirds on seven Pacific islands; they’re currently crafting solutions for the Pigeon Guillemot colony on Alcatraz. Each engagement has brought unique design challenges, Hester says: “Even the same species in different locations can need very different things.” 

The Wedge-tailed Shearwaters on Oahu, for one, normally nest in natural crevices like rock piles or in burrows the birds dig themselves. To keep the shearwaters cool underground, the partners designed nests with heat shields to block the sun and small flaps that open like louvered windows to increase airflow. Other times, the nests are called to outlast other creatures, whether larger animals galumphing over the structures or predators looking for a seabird snack. On the Channel Islands, boxes inhabited by the svelte Ashy Storm-Petrel were getting flipped over by ravens. Ultimately, the team realized that the individual nests weren’t heavy enough to withstand outside force, so they tried something new: a petrel triplex that couldn’t easily be moved. 

In some cases, the nests’ impact on breeding success could play a role in fending off the threat of extinction. Those are the stakes for the African Penguin, a stocky, pink-spotted species on Africa’s southern coast whose numbers have declined by 95 percent and are continuing to worsen. Wooden and fiberglass nest boxes have long provided vital breeding spots for the penguins, as the guano they would normally burrow in was historically harvested for fertilizer. The need for effective shelters is ramping up: Climate change is bringing more extreme storms to South Africa, just as significant a problem for the penguins as heat. Without a suitable refuge for chicks, says marine ecologist Lorien Pichegru, “they can die in one night.” 

But just as in California, conservationists began to realize that some existing structures were “cooking the eggs,” explains Pichegru, who has studied the penguins and their relationship with commercial fishing for 15 years.  Though well-intentioned, trying to provide ad-hoc solutions for the birds might have been making their outlook worse. “If you don’t have the science,” she warns, “you can kill the species.”  

Researchers toyed with nests made of cement, fiberglass, and vegetation before turning to a pot-like ceramic design that mimicked some qualities of the penguins’ natural burrows. After five years of deployment, they found ceramic nests gave chicks the highest survival rates of any material, and that the containers can cut ground temperatures by as much as 50 degrees Fahrenheit. The experiment also demonstrates the importance of staying attuned to individual colonies’ needs, since different nest materials showed promise at different test sites. In any case, the penguins “really like the shelters,” Pichegru says—and the new ceramic versions are expected to last much longer than their wooden predecessors.  

That durability is one of clay's biggest strengths. “We’re trying to future-proof them for 100 years,” Lynch says of the nests. That also means thinking about the warming that could develop decades from now. His designs aim to cut air temperatures by several degrees more than their inhabitants currently need for survival. 

Building nests to last is also a way to make the most of limited funding. Finding grants to create the nests has been a persistent challenge, Lynch says—and unfortunately, there's no built-in consumer demand for these products. (“It’s difficult to sell sculptures to birds,” he laments.) Lynch is now looking for ways to cut down on the time and effort involved in getting each site up and running. In addition to finding a cost-effective site for producing the nests at greater scale, he’s turning his attention to creating a smaller number of designs that can be broadly applicable to more than one site.

Though not all species are well-suited for artificial nests, Oikonos does expect ceramics could make a difference for some birds that don’t rely on nest boxes today. “In the long term, if there are places where seabirds are having some issues with heat exposure, even in their natural sites, we could consider artificial nests as a way to give them resiliency,” Hester says. Many bird species can’t just up and move to a new habitat, she notes, so they’ll need support to stay in place as their current homes change. 

Even as the ceramic nests promise a longer-term solution than their wooden predecessors, they’re not expected to last forever. As conditions in many ecosystems worsen, a hunk of clay won’t be enough to outlast a variety of climate-induced shifts, Warzybok acknowledges. “Ultimately, another 50 years from now, depending on what happens with the Earth’s climate, artificial habitat as we know it right now might not be suitable,” he says. But these innovations are buying needed time, and every chick that makes it through the coming years is a bridge to a more durable future.