Winning and Losing: Rabbits versus Virus

Invasive rabbit eating invasive rabbit-resistant plant in Australia (photo from Wikimedia Commons)

You would not think that something this cute could be a problem but European rabbits (Oryctolagus cuniculus) have plagued Australia for 160 years. After a century of recurring population explosions (think “plagues of locusts”!) scientists found a virus that kills only European rabbits. They introduced it in 1950 and it worked amazingly well for a while but the rabbit and the virus both evolved. Here’s their story.

Introduced for hunting in Geelong, Australia in 1859, the European rabbit immediately went feral and the population went out of control. Without any predators they covered most of the continent by 1910.

Range of the European rabbit; pink means “Introduced” (map from Wikimedia Commons)

Periodic population explosions, called rabbit plagues, became the norm. The rabbits eat everything. They devastate native plants, push out native animals, denude the countryside and cause dust bowls. In the photo below, at dusk, they are everywhere but probably not a plague yet since there’s still some grass.

So many rabbit holes. No trees or shrubs (photo from Wikimedia Commons)

Hunting and poisoning were ineffective.

Then in 1950 scientists found a virus in South America, called myxoma, that killed European rabbits. They released it in Australia (and in France) and it cut the rabbit population by 99%. Wow!

But a few rabbits lived and so did the virus. Science Magazine reports that “within a decade, rabbit numbers were on the rise again as some evolved resistance to this deadly infection and the virus itself became less deadly.”

This month, a new DNA study of both the rabbit and the virus shows that:

Rabbits on two continents evolved the same genetic changes to beat back the virus—before the virus itself changed and regained the upper hand. […and…] In the 1970s the virus developed a greater ability to suppress the rabbit’s immune responses. That change, as well as the natural emergence of another rabbit-killing virus, has caused populations to decline again.

— Science magazine, 14 February 2019

The arms race continues.

Don’t worry about the rabbits. They had another population explosion in 2004. At last count there are about 200,000,000 of them in Australia.

After all, they breed like rabbits.

For more information, read “Seventy years ago, humans unleashed a killer virus on rabbits. Here’s how they beat it” by Elizabeth Pennisi in Science Magazine.

(photos and range map from Wikimedia Commons. click on the captions to see the originals)

Rescuing Baby Flamingos

A rescued lesser flamingo chick in South Africa, Feb 2019 (photo courtesy the National Aviary)

When severe drought, high temperatures and failing infrastructure hit Kamfers Dam in Kimberley, South Africa, the lesser flamingo colony that nests there was forced to make a dreadful choice. The lake usually provides food and their island provides shelter but the water was gone. Incubating adults were dying of dehydration. If the colony stayed, all would die so they abandoned this year’s breeding attempt — eggs and chicks — to live and breed again.

Kamfers Dam is a privately owned dam just north of Kimberley, about halfway between Johannesburg and Cape Town, South Africa. The site was originally an ephemeral wetland but became a permanent lake thanks to runoff and treated wastewater from the town of Kimberley.

In 2006 people noticed that the lake attracted a Near Threatened species, lesser flamingos (Phoeniconaias minor), so they built an S-shaped breeding island for them (pin on map above). At the height of the breeding season it’s covered in tens of thousands of flamingos.

S-shaped island, lesser flamingo breeding colony at Kamfers Dam as seen from the air (photo from Wikimedia Commons)

Kamfers Dam is one of only six lesser flamingo breeding sites in the world and an international birding hotspot … until this year.

Lesser flamingos at Kamfers Dam in 2008, a wet year (photo from Wikimedia Commons)

In January, because of severe drought and high evaporation, a large part of the lake went dry. The lake level could not be restored by the water treatment plant because of their own failing infrastructure.

The flamingos abandoned their desiccated colony, so people went out to rescue the chicks. Click here or on the screenshot below to see a video of the rescue posted by Saan Staan Kimberley on Facebook.

Video of Kamfers Dam flamingo rescue by Saam Staan Kimberley on Facebook

2,000 flamingo chicks and eggs, some in the process of hatching, were rescued by volunteers and taken to shelters around South Africa.

Rescuing a Kamfers Dam flamingo chick (screenshot from Saam Staan Kimberley on Facebook

Then the hard work began — three to four months of feeding and monitoring thousands of flamingo chicks, many of whom arrived in bad shape from dehydration and starvation. Added to that is the challenge of not allowing them to imprint on their human rescuers. South Africans made a worldwide plea for volunteers.

The National Aviary stepped up to help. Terry Grendzinski, Supervisor of Animal Collections and avian specialist, knows all about raising baby flamingos so she flew to the SANCCOB rescue center in Cape Town. In the photo below she feeds one of the rescued chicks while wearing pink sleeves and back gloves to mimic the appearance of the chick’s parents. Click here to watch a video of the feeding.

So far, so good. The chicks are growing, preening and sunning in their enclosure (video below). Some are already standing on one leg!

Thanks to this massive rescue effort, this year’s lesser flamingo breeding season at Kamfers Dam will have a silver lining. You can donate here at the National Aviary to help these baby flamingos.

(credits: rescued chick at top, Terry G feeding a chick, and video of chicks in blue enclosure courtesy of National Aviary. Map of Kamfers Dam embedded from Google Maps. Video and screenshot of rescue at the dam from Saam Staan Kimberley on Facebook. Click on the captions to see the originals)

Named For His Crest

Brahminy starling in India (photo by Allan Hopkins on Flickr, Creative Commons license)

The brahminy starling (Sturnia pagodarum) from the Indian subcontinent was named for his black crest because it resembles the sikha hairstyle worn by Brahmins. He looks like a Brahmin when his feathers are at rest (above).

However, he raises his head feathers frequently.

Brahminy starling at Gilgit-Baltistan, Pakistan (photo by Imran Shah on Flickr, Creative Commons license)

Watch his crest as he sings in this video.

He’s a pushy bird whose shape, behavior and song remind me of our European starlings (Sturnus vulgaris). He’s not in the same genus … but close.

(photo by Allan Hopkins on Flickr, video by Jerubal on YouTube)

A Peregrine Hero Has Passed

Among the heroes of the peregrine falcon’s restoration in North America, Tom Cade was legendary. During his lifetime peregrines went from plentiful to nearly extinct. Today their population is healthy and growing, thanks in great part to Tom Cade’s efforts and dedication. He died this month at age 91.

Tom Cade was a falconer nearly all his life. He became hooked on peregrines at age 15 when one flew close overhead on its way to capturing prey. That was in the early 1940s when the peregrine population was still healthy in North America.

By the mid 1960s Dr. Cade was the head of Cornell Lab of Ornithology, the peregrine population was in free fall, and he could see it happening. The situation so alarming that he and other raptor experts were desperately trying to find out why before it was too late.

In 1965 they convened a conference about the peregrine’s decline at the University of Wisconsin, Madison that became the catalyst for peregrine recovery. At that point they knew the decline was due to DDT and dieldrin but they had no proof. (Proof came later from Derek Ratcliffe.) Meanwhile, agricultural experts argued it couldn’t be caused by pesticides; the pesticides were so useful.

In a 2015 video on the 50th anniversary of the Madison Conference, Tom Cade told how the conference changed the peregrines’ future. The transformational moment came when Jim Rice, a renowned falconer and naturalist from Pennsylvania, spoke nine words. It changed Tom Cade’s life. See him tell the story here.

After the conference Tom Cade was key in all that happened next, especially in shaping the captive breeding program and peregrine reintroduction. DDT and dieldrin were outlawed in the early 1970s. By 1999 peregrine falcons were plentiful enough in the western United States that they were removed from the Endangered Species List.

In 1970 Tom Cade co-founded The Peregrine Fund and worked with them for the rest of his life to conserve raptors around the world. See their tribute and remembrance video here.

We all stand on the shoulders of the great conservationists who went before us. We mourn Tom Cade’s loss but we celebrate his incredible contribution to conservation and to peregrine falcons.

Thank you, Tom Cade. Your inspiration lives on.

Read Tom Cade’s obituary in the New York Times. His book, Tom Cade: A Life in Science and Conservation by Tom Cade and Clinton M. Blount is available here on Amazon. The cover, which illustrates this article, shows Tom Cade with his gyrfalcon, Krumpkin, 2008.

(credits: Information on Tom Cade’s life is drawn in part from his obituary in the New York Times. photo: Cover of Tom Cade: A Life in Science and Conservation by Tom Cade and Clinton M. Blount via Amazon)

Sap Freezing

Frozen sap of red oak, 10 Feb 2019 (photo by Kate St. John)

The weather this month has been up and down like a yo-yo: A low of 6oF on February 2, highs in the 50s and 60s for six days, then a low of 14oF on February 9. During those warm days the sap started running in the trees. I wouldn’t have noticed except …

On February 10 during a walk in Schenley Park I found flash-frozen sap on the damaged trees. At top, a fallen red oak made a red-orange waterfall. Below, a small amount of sap in a fungi-encrusted tree dripped like orange ribbons.

Sap runs and freezes inside healthy trees, too. We just can’t see it.

(photos by Kate St. John)

Gifts From Crows

Four years ago in Seattle, eight year old Gabi Mann consistently fed and interacted with the crows in her backyard. She formed such a tight bond that she could recognize individual crows by sight and gave them names. The crows rewarded her by bringing gifts.

Many animals give gifts to members of their own species but crows and other corvids are the only ones known to give gifts to humans. As John Marzluff explains in the video, crows will do this for people who feed them a lot and pay attention to them, or even rescue them.

When I read about this several years ago in Marzluff’s book Gifts of the Crow, I briefly thought about trying to make friends with crows but decided it would be a difficult relationship. If your friendship with crows is based on food they remember your generosity and bring their friends. Lots of friends. They can be quite demanding and don’t understand if you stop. Not everyone appreciates this.

Gabi’s story made international news in February 2015 but we don’t hear about it anymore. Six months after this video was filmed two of Gabi’s neighbors sued, demanding $200,000 and a court order prohibiting the Mann family from putting out more than a 1/4 pound of bird food. It took a year to settle the lawsuit; the details were not made public.

Crows remember the faces of those who are mean to them and those who are especially kind. I’m sure that a few special crows remember Gabi.

(video from BBC on YouTube)

Love Is In The Air

Harmar bald eagle calls from her perch (photo by Gina Gilmore)

Love is in the air at the Harmar bald eagle nest. Gina Gilmore saw lots of activity last weekend.

Sometimes the female calls for her mate (above). He flies in to see her and they mate (on 8 Feb).

Harmar bald eagles mating, 8 Feb 2019 (photo by Gina Gilmore)

… and mate again (on 10 Feb).

Harmar bald eagles mating, 10 Feb 2019 (photo by Gina Gilmore)

They’re getting ready to nest, though their first egg is at least a week away, maybe more.

Harmar bald eagles near each other (photo by Gina Gilmore)

The Harmar pair historically lays 10-18 days later than the Hays bald eagles whose first egg arrived this week on 12 Feb 2019 at 6:45pm. In 2015-2018, Harmar’s first egg was between February 20 and March 9.

This year there’s no camera on the new Harmar nest so we’ll have to watch the female’s behavior to know when her first egg arrives.

In the meantime love is in the air. Happy Valentine’s Day!

(photos by Gina Gilmore)

How Many Blue Jays?

Great Backyard Bird Count 2019

In the winter of 2012 Pittsburghers noticed we had very few blue jays in our area. It was such a mystery that I posted an article in February asking folks to tell me if they’d seen any blue jays lately. Seven years later the responses are still coming in.

Most people respond when they don’t see any blue jays because they miss them. It turns out that blue jay frequency varies throughout the year and can drop locally when the habitat changes, especially if oaks are cut down. (Blue jays rely on acorns.)

Our blue jay count surges during spring and fall migration because a lot of them breed north of us. In Allegheny County (Pittsburgh) there’s also a mysterious mini-surge every year in mid February. What’s that about?

eBird frequency of blue jays in Allegheny County, PA, 2014-2019

See seven years of blue jay reports and musings at Have You Seen Any Blue Jays Lately?

Count your own blue jays during the Great Backyard Bird Count this weekend. How many birds will you find?

(image credits: Great Backyard Bird Count poster, eBird report on frequency of blue jay sightings in Allegheny County, PA, 2014-2019; click on the captions to see the originals)

Imprinting Error

In 2011 crane watchers in Homer, Alaska noticed that a single Canada goose was convinced he was a sandhill crane. How did this happen? And can it be undone?

As described by Encyclopedia Britannica, imprinting is a form of learning in which a very young animal fixes its attention on the first object it sees, hears, or is touched by and thereafter follows that object.

Imprinting is especially important for nidifugous birds — species that walk away from the nest shortly after hatching — because they must immediately follow their mother in order to survive. They imprint by sight and the lesson lasts a lifetime. If the first thing they see is their mother or another member of their own species, life is good. If not, they grow up believing they are another species and will never find a mate.

Imprinting happens at different times for different species so wildlife centers use surrogacy techniques, described here at the Wildlife Center of Virginia, to insure that baby birds don’t imprint on humans. If they do they cannot be released in the wild.

Human imprinting is well known among cranes so caregivers in the Whooping Crane Recovery Program dress in crane costumes when in sight of the young birds.

Whooping crane costume worn by biologists (photo by Steve Hillebrand, USFWS)

Birds use filial imprinting but there are other forms. Studies have shown that we humans prefer the first computer software we use and then compare all new software to that first and favorite app. It’s a form of imprinting called Baby Duck Syndrome. “I don’t like this; it doesn’t work like Microsoft Word.” Quack! Quack!

As for the Canada goose in the video, observers speculated that the bird’s mother laid his egg in sandhill crane nest. When he hatched he saw a sandhill crane and imprinted on the wrong species. He’s the victim of an imprinting error.

(video by Nina Faust on YouTube. photos from Wikimedia Commons; click on the captions to see the original)

Watch a Nest in Bermuda

Screenshot from the Bermuda cahow cam at Cornell Lab

Nesting season began last month for this pair of Bermuda cahows when the female laid her single egg on 10 January 2019. The parents are now taking turns at incubation duty. They expect the egg to hatch in early March.

Watch them in their nest burrow at Cornell Lab’s Bermuda Cahow Cam.

And for a preview of things to come, here’s a video of last year’s activity.

(screenshot from the Bermuda cahow cam and a video of 2018 Bermuda cahow highlights, both from Cornell Lab of Ornithology)