california condor


DDT: Another Challenge for Condors

Rachel poses for a photo with Jake the sea lion at the Zoo's Wegeforth Bowl.

Rachel poses for a photo with Jake the sea lion at the Zoo’s Wegeforth Bowl.

Recently I had the opportunity to meet Jake, a star sea lion at the San Diego Zoo’s Wegeforth Bowl. When a sea lion like Jake leans in for kiss, what is the first thing you think of? Perhaps you wonder if he brushed his teeth or if there is a towel near by to wipe away the slobber? In any case, I bet you wouldn’t wonder, as I did, about how many environmental contaminants are present in his blubber. Sure, this may sound a bit grim and out of place, but I can assure you that my reasons for thinking this are part of a larger, intriguing story, in which I am completely immersed as I pursue my master’s degree through the University of Missouri. This story involves a pesticide that was banned 40 years ago, the Los Angeles County sewer system, and San Diego Zoo Global’s continued commitment to the recovery of the California condor.

No need to worry about Jake and other sea lions living in zoos, as there are relatively low levels of contaminants present in their tissues. Those living off of the California coast, however, conceal some of the highest detectable levels in any marine mammal species of DDE, the breakdown product of the pesticide DDT. How did levels of DDE come to be so high in sea lions? The answer is shockingly simple. From the 1940s to 1970s, the world’s largest manufacturer of DDT dumped hundreds of pounds of it down the drain daily, where it traveled through the Los Angeles sewer pipes offshore to the Palos Verdes shelf. This dumping occurred over 30 years ago; however, these chemicals are particularly resistant to degradation and still exist in shelf sediments. As tiny critters feed on the sediments, they accumulate DDE. From the smallest invertebrates to fish and larger animals, more and more DDE creeps its way up the food chain to a top predator, the sea lion.

As sea lions migrate up the coast, they take DDE with them. Some do not survive the annual journey and therefore become part of a larger food web that includes the California condor. With over 50 reintroduced condors circling the coastal cliffs, it is a real possibility that a beached sea lion would become a welcomed scavenging opportunity. While this find is an amazing feast for a condor, should we be concerned about the DDE it conceals?

Fuego hatched in 2008 at the Los Angeles Zoo and was selected to fill the nest of his soon-to-be foster parents Amigo and Cosmo of Big Sur, California. His foster parents taught him the skills needed to survive in the wild, including two wildfires!

Fuego hatched in 2008 at the Los Angeles Zoo and was selected to fill the nest of his soon-to-be foster parents Amigo and Cosmo of Big Sur, California. His foster parents taught him the skills needed to survive in the wild, including two wildfires!

To answer this question, we can imagine traveling the California coast on a birding tour in the mid-1900s. We would start along northern Channel Islands where the peregrine falcons are being reintroduced after a population crash. Next, at Santa Barbara Island, we could see a shrinking cormorant population that hasn’t produced a chick in years. Finally, on Santa Catalina Island we would look for a bald eagle, but without luck as they have disappeared. Each of these populations has one thing in common; birds were exposed to high levels of DDE, and they produced notably thin eggshells.

Reintroduced condors currently feed higher up the food chain than the above-mentioned coastal birds, and as you may have already guessed, are producing thin-shelled eggs. Our colleagues at Ventana Wildlife Society have found that eggshells of coastal birds are 34 percent thinner than those of inland birds. This has contributed to a 50 percent decrease in successful hatching of coastal chicks. This discovery has led managers to successfully take in eggs from the wild, incubate them in captivity, and allow the wild parents to incubate and fledge captive-laid eggs.

Multiple lines of evidence suggest a link between thin eggshells and DDE exposure in coastal condors, but how can we possibly be sure without exposing condors to harmful chemicals? DDE is an endocrine disrupting compound (EDC). It can disrupt normal endocrine (hormone) pathways and functions, like reproduction, by activating hormone receptors, producing an unnatural hormone-like signal, ultimately resulting in weak eggshells. Luckily for the condors, our lab is developing a reliable assay within a test tube to determine the sensitivity of condor receptors to DDE and other EDCs. Determining which EDCs most strongly interact with condor receptors gives us a clue as to which will be most disruptive to condor reproduction. Connecting this knowledge with EDC assessments of habitats will assist conservation managers in locating release sites for California condors. Our hope is to safely release these magnificent birds into a historic habitat that provides a rich, contaminant-free diet, allowing the hatching of many wild condors in the future.

Rachel Gerrard is a research technician for the San Diego Zoo Institute for Conservation Research.


The Condors Next Door

Pshan rubs his head on the roosting platform next to Towich.

Screenshot: Pshan rubs his head on the nest ledge next to Towich.

Normally, at this time of the year, Condor Cam viewing is a little slow. The chick has been moved to our socialization pen in preparation for eventual release to the wild and the parents, Sisquoc and Shatash, won’t start their breeding season until late October/early November. But this year is different! Sisquoc and Shatash’s neighbors are still raising their chick, and we were able to shift the Condor Cam pen camera to peek in on them.

The male is this pair is Towich (pronounced TOH-witch) and the female is Sulu (SOO-loo). Towich is wearing yellow wing tags, numbered 135; Sulu is not wearing any tags. Towich hatched at the Los Angeles Zoo, one of our valuable partners in the California Condor Recovery Program, in 1996. He was released to the wild in southern California in 1997 but was recaptured and returned to captivity when he started showing interest in humans. More than likely, he was fed by people when he was young, causing him to lose his wariness of them. He is no longer suitable as a release bird. Towich’s story serves as an essential reminder that when viewing condors in the wild (or any wildlife, for that matter), it is of the utmost importance that we do not feed them or approach them too closely. Getting that extreme close-up picture or having the thrill of feeding a wild animal is not worth having the condor spend the rest of its life in a cage.

Sulu hatched at the San Diego Zoo Safari Park in 1990, and she has lived here with us her whole life. Towich is her second mate. She was separated from her first mate in 2000, when it was determined that she and Towich were a better genetic pairing. The pairing process in a breeding program can sound a bit clinical, especially in a species such as the California condor, whose population dropped to only 22 birds in 1982, but we have to be very careful who gets paired with whom in order to maintain as much genetic diversity as possible. Despite the lack of romance in being paired together, Towich and Sulu have developed into an awesome couple. They seldom squabble over food; they often perch near each other in the flight pen; they have excellent nest exchanges when incubating eggs or brooding chicks; and they seem to like to sit or lay down together, along with their chick, in the nest box or the roost.

The chick they are raising this year is Pshan (Puh-SHAWN), and he is 144 days old (as of September 17, 2013). Towich and Sulu are not Pshan’s biological parents, though. Towich and Sulu’s egg was needed at the Los Angeles Zoo this year, so we delivered it to that zoo before hatching. It hatched under a different pair of condors and will eventually be released somewhere in California. Now that Towich and Sulu were without an egg, we had the opportunity to give them a different egg, one that we were planning on raising using a condor puppet. One of our condor pairs is not very good at sharing nesting duties and often squabbles over chicks when they hatch. Therefore, to ensure the safety of the chick, we don’t let that pair parent-rear anymore. Pshan is the chick that hatched from the egg fostered to Towich and Sulu. Fostering is a common technique used in avian breeding. The parents usually accept the new egg and hatch it and raise the chick as if it was their own.

Like Sisquoc and Shatash, Towich and Sulu have done an exemplary job in raising their chick. Pshan hatched April 27, 2013, and is about a month younger than Cuyamaca. He is starting to come out onto the nest ledge more often. By the end of the month, he should be ready to fledge, or leave the nest. At that point, he will receive his wing tag and be moved to the socialization pen to be introduced to Cuyamaca and the other chicks from this year.

Many Condor Cam viewers have requested photos of Cuyamaca in her new pen. We, hopefully, will be posting some soon. She is handling the socialization process like a champ.

Also, we received word from the field biologists at Bitter Creek National Wildlife Refuge recently. Saticoy, the Condor Cam chick from last season (and Cuyamaca’s older brother), has not been released to the wild yet. He is doing very well in the pre-release pen and should be flying free by the end of September! When this happens, we’ll let you know and, we hope, will have some pictures to show you, too.

Have fun with Towich, Sulu, and Pshan!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Condor Moving Day.


Condor Chick: Nest Barrier

Condor chick Cuyamaca as seen on Condor Cam

Condor chick Cuyamaca as seen on Condor Cam

One of my favorite sayings is “boring is good.” When things are boring, everything is going according to plan; excitement is often the result of something going awry. As many Condor Cam viewers have experienced, the rearing process for a California condor can be long and slow—some may even say boring. It makes sense, though, for a condor to develop so slowly; she has lots of growing to do! When our chick, Cuyamaca, hatched, she weighed approximately 6.3 ounces (180 grams). When she reaches her fledge weight of 17 pounds (8 kilograms) or more, she will have increased her hatch weight by 44 times! I, myself, have only increased my birth weight by 19 times.

On July 15, at 112 days of age, Cuyamaca took her most recent step toward leaving the nest: she jumped up onto the barrier between her nest box and the adjoining roost area. She quickly hopped back into her nest, but that’s okay. There’s no hurry to fledge, or leave the nest, just yet. Her feathers still need time to fill in. In the meantime, hopping up and down from the barrier will exercise her muscles and improve her balance. Any day now, she will hop into the roost area on the other side of the barrier. Here, she can look into the flight pen where her parents, Sisquoc and Shatash, are. She also will be able to warm herself in the sun, if she so chooses.

The next step of Cuyamaca’s development will be to fledge. When she is ready, she will jump off of the 8-foot-tall (2.4 meters) nest ledge. She will either slow her fall to the ground below the ledge or fly to a nearby perch. We consider her fledged when she can get up on a perch by herself. The youngest we have seen a condor chick fledge here at the San Diego Zoo Safari Park is 123 days old. Sometimes chicks have waited until over 165 days. It all depends on the chick.

The parents tend to be very vigilant at this phase of their chick’s development. It could appear over-protective to us, but keep in mind that they have invested an entire breeding season and lots of energy into this one chick. It benefits them greatly to make sure that their sole offspring is safe, healthy, and strong. They usually don’t coax or pressure their chick to leave the nest; on the contrary, we have seen parents make sure their chick doesn’t stray too far from the nest if it’s not ready yet. The parents will usually perch and/or roost near the fledgling. They also will join her when she finally starts going to the feeding area of the flight pen. Most of the time, though, they will push her aside and eat first, feeding her when they are done. In condor culture, the bigger, more dominant birds usually eat first while the subordinate birds wait their turn. The earlier Cuyamaca learns this from her parents, the better she will assimilate into a wild population after she is released. Don’t worry—Sisquoc and Shatash won’t let Cuyamaca starve! They will continue to feed her even when she is out in the flight pen. Eventually, she will eat more and more on her own.

Depending on Cuyamaca’s development and activity levels, we will try to switch the Condor Cam view from the nest box/roost area to the flight pen. You’ll be able to see the roost area, most of the perches in the pen, the feeding area, shade areas created by plants, and the pool, where she can either drink on her own or bathe (one of my favorite condor activities to observe!). The view will be wide, so detail will be harder to discern. Also, we do minimal maintenance in the pen once the chick is large enough to look over the nest box barrier, so the pen has lots of plant growth and dried food (animal carcasses) in it. We limit our activities in/near chick pens so as not to expose the chick to humans, thus desensitizing her to our presence. We have found that chicks raised in isolation from humans tend to be more successful once they are released to the wild. The flight pen won’t look as nice as an exhibit you might see at the Zoo or the Safari Park, but Sisquoc and Shatash prefer it that way if it means we stay away from their precious chick!

Thanks so much to all of our faithful and dedicated Condor Cam viewers. Soon, your support and devotion will be rewarded when our “little big girl” spreads her wings and takes that next step. Rest assured, though, that Cuyamaca’s story will be far from over!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Condor Chick: Exercising Those Wings.


Condor Saticoy at Release Site

Condors Nechuwa, Sukilamu, and Saticoy take in the view.

Saticoy (far right) and his fellows are acclimating to their new home in the Bitter Creek National Wildlife Refuge.

Some of our devoted condor fans have been asking about Saticoy, the California condor chick who hatched and was raised by his parents while on the San Diego Zoo Safari Park’s Condor Cam last year. For those who are new to Condor Cam, Saticoy is the older sibling to this year’s chick, Cuyamaca.

On April 11, Saticoy was transported to his release site with two other condors who hatched at the Safari Park last year, Nechuwa and Sukilamu. These three young males are being housed in the Bitter Creek National Wildlife Refuge in a flight pen with a wonderful view of the quiet, wide-open spaces of the Refuge. Beautiful wildflowers growing all over the grassy, rolling hills lead to the canyons and mountains that provide prime condor nesting habitat. The Refuge is located just north of Santa Barbara in southern California’s Kern County.

The flight pen is visited by curious condor neighbors.

The flight pen acts as a hacking site, or a place where the young birds become familiar with their surroundings before they are released to the wild. They can acclimatize to the weather and wind. Also, there are 66 other condors flying free in this region, and many of them frequent the hillside where the flight pen is located. This allows the resident condors to meet the new, young release candidates; when the young birds are released, they won’t be complete strangers to the free-flying condors. When we put Saticoy (wearing wing tag #36), Nechuwa (wing tag #37), and Sukilamu (wing tag #43) in the flight pen, four wild condors were already watching from the outside, curious about their new neighbors.

Saticoy and his pen mates will stay in the flight pen through the summer. If all goes well, the field biologists will release them to the wild sometime in September, about 18 months after Saticoy’s hatch. As you can see, California condor development is a long and involved process!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Condor Chick: 1st Exam.


Condor Chick Watching: Age 30 to 45 Days

Cuyamaca does some preening in the nest box.

Cuyamaca does some preening in the nest box.

At about one month of age, our California condor chick Cuyamaca (pronounced “Kwee-ah-MACK-ah” and meaning “through the clouds” in Kumeyaay), should weigh around 4.4 pounds (2 kilograms). The parents, Sisquoc and Shatash, may start leaving the chick alone overnight, sleeping near the nest. If the weather is still cool or it’s raining, they may continue to brood overnight until the weather improves. Even though the parents are increasing their time away from the chick, they remain VERY vigilant and protective of their nest and ESPECIALLY their chick. Some field biologists have even seen wild condor parents chasing black bears away from the nest area!

Up until now, the chick has been scooting around the nest on its tarsal joints. We refer to that as a tarsal crawl. It’s not uncommon, at this age, to see the chick standing all the way up on its feet, teetering around the nest, holding its wings out for balance. As its legs get sturdier, the chick may even approach the parent, begging for food. The wing-begging behavior we’ve been seeing will get more pronounced: lots of wing-flapping, head-bobbing, and trying to position itself in front of the parent.

It is possible that the parents, who are offering larger quantities of food per feeding session, might be providing a small amount of fur/hair in the chick’s diet. (Part of the adults’ diet includes mammals, like rats and rabbits.) Condors can digest just about every part of the animals they eat, except for fur. This fur accumulates in the digestive tract and is eventually regurgitated as waste. We refer to this as casting. A condor’s cast is composed of predominantly fur, whereas a cast from an owl has fur and bones; owls can’t digest bones, but condors can. We have seen condor chicks cast hair pellets as young as three weeks of age. When the chick casts, it throws its head forward several times, mouth open, until the pellet is ejected from its mouth. It can look like the chick is in trouble, but it is perfectly normal and good for the chick.

At around 45 days of age, Cuyamaca will get its first health exam. We will obtain a blood sample for the lab to make sure the chick is healthy and send a portion of this sample to a lab in the Genetics Division of the San Diego Zoo Institute for Conservation Research. From this blood sample, the geneticists can determine if Cuyamaca is male or female. Also during the exam, we will weigh Cuyamaca (the chick should weigh between 7.7 and 8.8 pounds or 3.5 and 4 kilograms), and we will inject a transponder chip as a form of identification. It’s the same kind of chip you can get for your dog or cat at the veterinarian. Most importantly, this exam allows us to administer a vaccine for West Nile virus, a disease that originated in Africa and was accidentally introduced to North America by humans. North American animals, including condors, usually don’t have a natural immune response to West Nile virus, so we are trying to give our chicks as much of a head start as we can.

This exam will be the first time that Cuyamaca will see humans, so it will naturally be disturbing for the chick. We try to be as quick as we can (9 to 10 minutes) to minimize the disturbance. Additionally, we will keep Cuyamaca covered with a towel to reduce its exposure to humans and to provide it a bit of security. Sisquoc and Shatash are usually away from the nest when we perform the procedure to keep them as calm as possible, as well. We have to keep in mind that we don’t want Cuyamaca to become accustomed to or feel reassured by our presence; we want it to be a wild condor, uninterested and wary of humans, so that it may someday fly free in California, Arizona, or Mexico.

Cuyamaca will look very large at this age compared to how big it was at hatch, but remember that it is still less than half of its adult weight. There is much more growth and fun to come on Condor Cam!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Condor Chick Watching: Age 3 to 4 Weeks.


Condor Chick Watching: Hatch to 1 Week

Shatash sits tight.

Shatash sits tight.

As many regular Condor Cam viewers witnessed, our California condor chick hatched on March 26, 2013, weighing around 180 grams (6.3 ounces). The hatching process can be grueling, so afterward, the chick usually rests a lot and is brooded (sat on) by the parents. We often call this sitting tight. The parents are providing protection and warmth, especially while the newly hatched chick is drying off.

Being weak and wobbly, the chick often is hard to feed, but that is okay. The chick is getting nutrients from the yolk sac that it absorbed into its belly just before hatching. After about a day, the chick can hold its head steady, and the parents then start providing food. They eat food we offer out in the flight pen, and then bring it to the chick in their crop (a bulge in their esophagus where they can store up to 3 pounds or 1.3 kilograms of food). The food is regurgitated for the chick, providing a warm and nutritious meal. Mmmmmmm!

The diet we provide varies, depending on the day, but it can include rabbits, rats, trout, beef spleen, and ground meat. While the chick is very young, it is often difficult to witness a feeding, since the parents are standing directly above the chick, blocking the camera’s view. If you see a parent slightly bobbing its head while standing over the chick, feeding is occurring. Feeding sessions are fairly short for small chicks, since their crop is only about the size of a lima bean.

Both California condor parents provide care for the chick. This drive is very strong, and it’s not uncommon to see the parents vying for time with the chick, especially immediately after hatching. This happens in the form of leaning into each other, pushing one’s way onto the chick; scooping the chick from one parent to the other; or nipping at neck skin or tugging at feathers to get the other parent to move. Usually, one parent acts more dominantly and controls the interactions a little more than the other parent. This time, mother Shatash took this dominant role, despite her being much smaller than Sisquoc. Other years, we’ve seen Sisquoc take this role. We interpret this periodic shift in dominance, and the other bird’s acceptance of this shift, as a very good trait in a condor pair. As time passes after hatch, they settle into a routine, and the nest exchanges become much calmer.

One viewer concern was the number of times the chick was stepped on by the parents. In many species, ranging from hummingbirds to elephants, babies get slightly squished by a parent. Usually, it’s just a minor misstep, and the baby lets the parent know with a brief vocalization. Condors are no different or no more fragile. They are very hearty little chicks! As young as four days of age, we have seen chicks sifting through the sand in the nest, picking up items on their own. We’ve even seen chicks swallowing small pieces of its eggshell for dietary calcium.

At the end of the condor chick’s first week of life it weighs around 10.5 ounces (300 grams). It is getting much stronger but is not venturing around the nest very much yet. Coordination is improving, and we can witness social interactions with the parents: nibbling, preening, and nuzzling. Every once in a while, you may see the chick quivering, almost like it has the hiccups. It is actually vocalizing. Condors don’t have a true voice box, or syrinx, like other birds, but they can make crude, primitive vocalizations. Adults may grunt, wheeze, or hiss. Chicks can make a high-pitched, scraping squawk, usually when begging or out from under the parents for too long.

The next few weeks of development are very exciting, not just for the condor family, but for any of us watching on the Safari Park’s Condor Cam. Stay tuned!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, The Next Chapter in the Adventures of Saticoy.


Next Chapter in Adventures of Condor Saticoy

California condor chick, Saticoy, as seen on Condor Cam in April, 2012.

California condor chick, Saticoy, as seen on Condor Cam in April 2012.

Our Condor Cam superstar from last season, Saticoy, is heading out into the wild blue yonder! We have recently received notification from the U.S. Fish & Wildlife Service that Saticoy will be released to the wild in California.

For those that are new to the San Diego Zoo Safari Park’s Condor Cam, Saticoy is one of our California condor chicks who hatched here last season and is the sibling of this year’s Condor Cam chick. He actually hatched live online on the morning of March 10, 2012. Thousands of lucky viewers logged on to experience this one-of-a-kind event.

Here at the Safari Park, we have been video-monitoring our condor nests for over 20 years, but 2012 marked the first time that a condor nest was available for viewing by the public. The parents (father Sisquoc and mother Shatash) did an amazing job of feeding and caring for Saticoy as he hatched and grew under the watchful and admiring eyes of all of his fans. When he hatched, he weighed around 180 grams and had a wingspan of only about 5 inches. Now, at 1 year of age, he weighs 17 pounds (nearly 8 kilograms) and sports a 9 1/2-foot wingspan!

Saticoy and two of our other youngsters, Nechuwa and Sukilamu, had their pre-shipment examinations on April 2. Our veterinarian staff gave them all health exams and took blood samples, making sure that they are free from disease before they are released to the wild condor population. They will be transported on April 11 to the Bitter Creek National Wildlife Refuge in the Los Padres National Forest of southern California. There, they will receive new wing tags, wing transmitters (so the field biologists can track them), and be socialized with another group of condors before they are finally allowed to fly free. The release date has not been set yet. It could be any time from late summer to mid-winter. We’ll try to keep you up to date on release location and date as we get notice.

With any luck, Saticoy will thrive in the wild and use the experience he gained from his parents, Sisquoc and Shatash, and his release mentor and cohort here at the San Diego Zoo Safari Park. As you stay tuned for more in the adventures of Saticoy, enjoy watching his younger sibling grow up on Condor Cam, and remember to vote for a name for this chick by April 15!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park.


Condor Egg is Hatching!

Shatash continues to incubate her pipping egg.

Shatash continues to incubate her pipping egg.

The big hatch day is quickly approaching, and our devoted California condor parents, Sisquoc and Shatash, have been patiently caring for and incubating their egg here at the San Diego Zoo Safari Park. Well, actually, they’ve been caring for a wooden egg that we refer to as a “dummy” egg. We use a dummy egg as a type of placeholder until their real egg is ready to hatch. It’s not as if we don’t trust them with a real egg; on the contrary, they have proven to be very reliable parents! When we artificially incubate the eggs and let the parents sit on a dummy egg, we can more closely and conveniently monitor the egg’s progress and offer any necessary assistance without disturbing the doting parents. When the real egg is about to hatch, we carefully switch it with the dummy egg.

California condor eggs start the hatching process after 53 to 56 days of incubation. The process can first be seen when the air cell begins to quickly expand. The air cell is a pocket of air at the big end of the egg. Next time you crack open a chicken egg at home, look for the air cell. Once the air cell expands against the embryo’s beak, the membrane of the air cell is pierced, initiating pulmonary respiration. This is the first time the condor chick is breathing air. The chick is breathing in more oxygen than can enter through the pores of the eggshell. Consequently, carbon dioxide builds up in the egg. This buildup stimulates the chick to start pushing from inside the egg until the shell is finally broken. A dime-sized bump is raised in the shell. This is called a pip.

Once the chick pips the shell, more oxygen can enter the egg, and the chick continues with the hatching process. Blood vessels lining the interior of the egg are shut off and the yolk sac is retracted into the chick via its umbilicus. We obviously cannot see these processes, but we can see the chick breathing, pushing or poking at the pip site, nibbling on shell membranes, and enlarging the pip site by breaking more shell. Every once in a while, we can even hear the chick squawk from inside!

When the yolk sac is fully retracted, and the blood vessels are ready, the chick begins to rotate inside the egg. As the chick pushes against the interior of the shell, it rotates inside the egg, breaking shell as it does so. As you can imagine, this is a very tiring activity for the little chick! The parents don’t break off any new shell for the chick, but they do remove broken pieces of shell. When the chick is almost fully rotated, it starts to push harder inside the egg, resulting in the shell expanding until the top of the egg comes off. This is called capping. At this point, the parents help the chick more, removing the capped shell or even pulling the bottom of the eggshell off of the chick. This is when we consider the chick hatched!

The pip-to-hatch period can vary for each species of bird, but for California condors it can last between 48 and 72 hours. We have seen some parent-hatched chicks take a little longer (~85 hours) to hatch with no ill effects.

Sisquoc and Shatash’s egg started the hatching process at 2 a.m., Sunday, March 24, when the chick pipped the shell. We returned the pipped egg to the parents at around noon, about 10 hours after pip. We quietly snuck into the nest box while they were out eating in their flight pen to exchange the real egg for the dummy egg. Shatash returned to the nest and settled back onto the egg, but now it is moving a bit and squawking underneath her!

If all continues to go well, we are expecting the egg to hatch around 2 a.m. on Wednesday, March 27. Of course, it could hatch before OR after that time, so keep checking in on Condor Cam. A good time range to expect a hatch is from 8 a.m. on Tuesday, March 26, to 3 p.m. on Wednesday, March 27.

Ron Webb is a senior keeper at the San Diego Zoo Safari Park. Read his previous post, Condor Egg is Fertile!


Condor Egg is Fertile!

A California condor egg is examined.

A California condor egg is examined.

We have good news to report: Sisquoc and Shatash’s egg is FERTILE! (See previous post, New Egg for Condors Sisquoc and Shatash.)

California condor Shatash laid the egg on January 27, and we are expecting it to begin the hatching process around March 23. So, it is over one third of the way through its 56-day incubation period. Condor Cam viewers have been watching Sisquoc and Shatash take turns caring for and incubating their egg. Well, actually, they’ve been caring for a wooden egg that we refer to as a “dummy” egg. We use a dummy egg as a type of placeholder until their real egg is ready to hatch.

It’s not as if we don’t trust them with a real egg; on the contrary, they have proven to be very reliable parents! When we place the egg in an incubator and let the parents sit on a dummy egg, we can more closely and conveniently monitor the egg’s progress and offer any necessary assistance without disturbing the doting parents. We weigh the egg every day and candle it every few days. When we candle the egg, we hold it up to a bright light that illuminates the interior of the egg, allowing us to see inside. We can monitor blood vessels, membrane development, embryo growth, and movement. By weighing and candling during the incubation period, we can make sure that the embryo is progressing normally, and if it isn’t, we can prepare to offer help if and when it is needed.

If all goes well during incubation and the egg begins the hatching process, we carefully switch it with the dummy egg while the parents are out in the flight pen eating or sunning. They usually don’t even realize we switched eggs on them; they just return to their incubation duties.

As previously mentioned, both parents take turns sitting on the egg. An incubation bout may only last a few minutes before the parent gets off of the egg and leaves the nest box, or it may sit for the whole day. When the parents take turns on the egg, we call it a nest exchange. Sometimes a nest exchange is immediate: one parent enters the nest, and the other parent gets off of the egg and leaves. Other times, a nest exchange may be long, leaving the egg unattended for up to 30 minutes while the parents are outside eating, bathing, sunning, or socializing. During a long nest exchange, the egg cools down, but not usually enough to endanger the egg, especially with successful and experienced parents like Sisquoc and Shatash. Many times both parents are in the nest area (one may perch in the nearby roost while the other sits on the egg) seemingly keeping each other company.

During nesting season, California condors can be surprisingly territorial and defensive of their nest. Usually, they are very mild-mannered and calm, but when they have a precious egg or chick in the area, they defend it. One of the field biologists in California reported a pair of condors swooping and chasing a black bear away from their nest! Despite being very tough and strong birds, they can be very gentle when it comes to caring for their egg or their chick. Keep checking in on Condor Cam to follow the progress of Sisquoc and Shatash’s egg and eventual chick!

Ron Webb is a senior keeper at the San Diego Zoo Safari Park.


Phantom Condor Chick Appears

A young, unmarked California condor soars in the skies of Baja California, Mexico.

A young, unmarked California condor soars in the skies of Baja California, Mexico. Photo credit: Juan Vargas

In the spring of 2012, our newest wild California condor pair in Baja California, Mexico, identified as #361 and #373, continued to show signs that they were incubating an egg by being more aggressive to the other condors around the feeding site and by spending a lot of time in a remote area dotted by deep canyons and precipitous cliffs. Their GPS wing transmitters indicated a near-exact position of where the nest would be out in the wilderness by latitude and longitude readings. Plugging these coordinates into our handheld GPS, Program Field Manager Juan Vargas and I struck out in September 2012 to try to find the nest, knowing that it was about 15 miles (24 kilometers) out to the remote south of our condor field station.

We traveled light and fast but only made it three quarters of the way there after three days through rough terrain and vegetation. With dwindling food and clean water, we decided to head back. Also, the GPS maps indicated that the nest was very high in precipitous terrain, and we were not carrying sufficient ropes and equipment to deal with it safely. Within condor release programs in the United States, if the nests are too difficult to find or ascend to, scientists rely on waiting for the young to fledge and show up at feeding sites, where they can be trapped and tagged later. We decided to do the same, since verifying the young at the nest would be too costly in terms of helicopter time, which would be the only way we could safely access it.

The chick and its mother, #???

The chick and its tagged mother at rest.

The downside to this decision was that the chick would not be inoculated for West Nile virus and would run the risk of catching the disease if we could not administer the vaccine. From our field station, Catalina Porras and crew analyzed both radiotelemetry and GPS data and estimated that the chick probably fledged in October. Over the three months that followed, only the behavior of the parents at the feeding site and their movement patterns continued to give us hope that there was indeed a chick flying around in the backcountry. We continued to scan the skies for a “tagless” condor with a gray head.

Finally, on February 4, 2013, Juan and a crew member observed a juvenile condor showing behavior that stood out from the others. Further scrutiny revealed that the black-headed youngster had no tags. It was hard to keep the excitement contained as we realized that the phantom chick had survived! As the new chick becomes accustomed to the other wild condors and the feeding site over the next few months, we are hoping to trap it, administer the West Nile virus vaccine, and tag it with GPS transmitters so we can safely follow its progress.Three condor pairs are looking like they may produce young this season. With luck, we may find more dark-headed condor young in the skies over the Baja mountains next year as well.

Michael Wallace is a conservation program manager for the San Diego Zoo Institute for Conservation Research. Read his previous post, Releasing Condors: Not So Easy.