Tag Archive: san francisco zoo


The challenges of motherhood are many.

It requires a ton of patience.

humming bird

A mama humming bird on her nest. Image taken at the San Franicsco Zoo.

humming bird

A mama humming bird on her nest. Image taken at the San Francisco Zoo.

You have to carry a lot of extra weight.

gorilla

Baby Hasani and his adopted mom. Image taken at the San Francisco Zoo.

You have absolutely NO privacy.

flamingo

A flamingo chick, hiding in the safety of his mom's feathers. Image taken at the San Francisco Zoo.

And let’s face it; your young won’t stop until they’ve sucked you dry.

elk

A young elk, getting a drink from mom. Image taken in northern California.

And the worst part is, one day you have your brood all together…

peahen

A peahen and her chicks. Image taken at the West Coast Game Safari Park in Bandon, Oregon.

But then you look up and they’ve all gone their separate directions!

peahen

A peahen and her chicks. Image taken at the West Coast Game Safari Park in Bandon, Oregon.

But wherever they go, they’re following in your footsteps.

peahen

A peahen and her chicks. Image taken at the West Coast Game Safari Park in Bandon, Oregon.

And they’ll always look up to you.

seagull

A seagull and her well camouflaged chick. Image taken at Sea Lion Cave, Oregon.

And need you and love you.

rhinos

A baby rhino with mama Elly. Image given to me by the San Francisco Zoo.

Thanks, mom, for handling all of these challenges LIKE A BOSS!!! Happy Mother’s Day!!!

See You Later…

 

alligator

An up close shot of a baby alligator. Image taken at the San Francisco Zoo.

It’s hard to believe I’ve been writing this blog for so long and yet I haven’t written about alligators until today. There are so many cool and amazing things about alligators, a lot of which are adaptations that are so efficient, they have been around in some form for millions of years.

Take the little dots all over their face, which you can see on Lafayette, the alligator shown above. Those little dots can feel vibrations in the water. Obviously this can help them find moving food. But it may also play a role in courtship. When alligators are courting, the males will make a low bellowing sound and blow bubbles and the vibrations these actions make in the water can be felt by other alligators. When they’re courting, they’ll also rub each others backs. Here is a great video of alligators making their bellowing sounds. I know is sounds really ferocious, but this is not the sound to worry about. When an alligator is feeling threatened (and therefore can be dangerous, although very few people are attacked and killed by alligators), they make a hissing sound. Hiss=bad.

I will reiterate, alligators are really not usually aggressive. They are territorial, so you want to leave them their space, but they don’t usually see people as food. We’re too big. It’s crocodiles you gotta watch out for. So…how do you tell the difference? Well, where are you? If you are not in the Southeastern United States or in the Yangtze River in China then you are looking at a crocodile. But if you are in the south east of the U.S., then you can encounter both. Crocodiles are generally going to be much bigger, although a small crocodile and a large alligator will be very close. Crocs will have a narrower snout and at least two of their lower teeth will be visible when their mouth is closed. Alligators have a more rounded snout and their bottom teeth don’t show when their mouth is closed.

 

claude

Claude, an albino alligator. Notice his "U" shaped snout and the lack of visible bottom teeth. Image taken at the California Academy of Sciences.

Still, my advice is to not get close enough to check out their dentition.

So, humans are not really on the menu for alligators, but as opportunistic carnivores, they will eat just about any appropriate sized meat, including fish, turtles, birds and whatever else they can grab. But, if not eating them for dinner or feeling threatened by them, alligators can sometimes live closely with other animals without any danger. Claude (above) got along quite well with his snapping turtle tank mates. And this baby alligator is enjoying a turtle bed:

 

alligator and turtles

Alligator Lafayette using his turtle tank mates as a bed. Image taken at the San Francisco Zoo.

While we’re looking at a baby alligator, their is a lot to be said about how these little cuties come about. As reptiles go, the alligator mom is very attentive to her young. She starts by making a nest for them. She makes a nest out of decaying material and in the decaying process it gives off heat. In a sense she makes a natural incubator. Whether or not a young alligator is hatched a male or a female depends on the temperature (one of the concerns about climate change is that it will skew the ratio of males and females for animals with temperature dependent sex determination) they are incubated at. Since the ones at the center of the nest will typically be warmer than those at the outside, this usually leads to a pretty decent mix of males and females. When the young are ready to hatch, they will start making hatching calls that sound like a video game laser or a chirp. They make these sounds while they are still inside of their egg! The sound lets mom know that it’s time to unbury her nest and carry her little hatchlings to the water very gently in her mouth. She will care for her young for up to 2 years after they are hatched, which is very important since there are many predators for a young alligator, including other alligators. If a young alligator makes a distress call, the females in the area that have young will come to the aid of that youngster, whether it’s their young or not.

Lafayette and turtle

Lafayette on his turtle tank mate. Lest you think that the alligator is always on top, I have definitely observed turtles climbing over their alligator tank mates as well. Image taken at the San Francisco Zoo.

This young alligator was not even two years old when this picture was taken. For alligators, that is just a baby. They can live to be 65-80 years old in the care of a zoological facility and even in the wild they are very long lived. And they are survivors. Because they have low energy demands and relatively slow metabolisms they can even go up to 2 years without eating at all, just relying on the stores of fat in their tails. 2 years! These traits plus one other really cool adaptation also gives them the ability to hold their breath in warm water for up to 30 minutes. That other adaptation? Well it’s a little piece of their anatomy that is very special. They breathe and circulate blood pretty much just like we do. They breathe air into their lungs. Blood comes through the lungs to get oxygen and then gets pumped out to the body then back to the lungs, to the body, to the lungs and so on. But their 4 chambered heart (like ours and their relatives the birds but different from other reptiles) has a shunt in it that allows them to bypass their lungs entirely. They can keep recirculating their blood through their body and getting every last bit of oxygen out of it without it going to the lungs to refill. What a cool trick! In fact if you lower the water temperature, because they are cold blooded their metabolism drops even more. The record for an alligator staying under water, albeit in near freezing temperatures was 8 hours! 8 hours without breathing!

Their lungs are no less special than their heart shunt when it comes to assisting them in their aquatic lifestyle. Their lungs, filled with air, provide quite a lot of buoyancy. The alligators use this to their advantage. When they want to dive under the water, they can shift their lungs towards their tail. This lifts their lower regions up and dips their head downwards, giving them the first little dive they need. They can also shift their lungs from side to side, to allow them to roll. If anyone reading this was a fan of the crocodile hunter, you’ll remember him talking about the animal’s “death spiral.” That was achieved by moving their lungs around inside of their chest cavity.

 

albino alligator

Claude's rock is heated and he enjoys basking on it, especially after a big meal. Image taken at the California Academy of Sciences.

albino alligator and turtle

See I told ya. A turtle climbing on an alligator. Image taken at the California Academy of Sciences.

As well adapted as alligators are, there has been just one force of nature that almost proved to be too strong for them. Yup. You know it. Us. Believe it or not, there was a time when alligator skin purses, belts and boots were super fashionable-to the point where alligators were declared “endangered” even before the Endangered Species Act was passed. Fortunately, protections were put in place and alligator farms were established. These farms were allowed to operate as long as they released at least 25% of their alligators into the wild. With all of the protections in place, alligators flourished again and they are doing really well. Although, they certainly still have some human induced problems…the most interesting one being an introduction of non-native ginormous snakes, Burmese pythons, in Florida. Alligators can eat the young of these snakes but the adult snakes can take on alligators. The fascinating part about it is that alligators, when stressed, can lower their metabolism substantially and reduce their heart rate. When a snake is constricting, and the alligator drops its heart rate to just a few beats per minute, the snake assumes it’s dead and begins to swallow it. However, the alligators sometimes seem to come back from the dead and begin to fight the snakes from the inside out! There have actually been instances where the snake finished eating the alligator and it burst open from the inside! You can see a great video of a partially swallowed alligator fighting back here.

Some cute

Hi Backyard Zoologist readers,

Sorry about the missing posts last week, as I’ve been super busy with family visiting and work. I will be starting up back on schedule again on Friday. Until then, have some cute:

chubby chipmunk

A chubby chipmunk. Image taken at Lake Tahoe, California.

Vanessa

Vanessa, the most beautiful chicken that ever lived. Image taken at the San Francisco Zoo.

cuttlefish

This cuttlefish is like "Please love me. I'm cute." Image taken at the California Academy of Sciences.

Barn Owl-Kid Style

barn owl sign

Barn owl sign for the San Francisco Zoo. Image taken in San Francisco.

A Virtual Tour of Rhinos

Black Rhino

This black rhino, Elly, has been part of a breeding program at the San Francisco Zoo.

It’s probably no surprise to regular readers that I have a soft spot for rhinos. This particular rhino, Elly, single hooved-ly pointed my life in the conservation direction. They are amazing animals. This post is going to primarily focus on black rhinos like Elly here, unless I specify otherwise, although much of the information will be true for most of the rhino species.

For example, all rhinos had enormous ancestors, including the largest land mammal that ever lived, the Indricotherium, which went extinct 10 million years ago.

 

Indricotherium

A life size model of an Indricotherium, an extinct mammal. Image taken at the California Academy of Sciences.

One of the things that animals in this group have in common is their hooves, which have three toes and make a print like the ace of clubs. Notice how this rhino has very similar feet to the Indricotherium model:

 

rhino

A black rhino. Image taken at the San Francisco Zoo.

This group also has a really tough, very thick skin. Their skin is so thick that they are protected from thorns and can travel through dense thorn bush where other animals find it hard to travel. Other animals can then take advantage of the paths created by the rhinos.

 

Greater one horned rhino

A close up of the thick skin of a Greater one-horned rhino, Gauhati, at the San Francisco Zoo.

This is the skin of a Greater one-horned rhino, which has a scientific name that always makes me smile- Rhinoceros unicornis. On this particular rhino, if veterinarians have to give him an injection, they must do so behind his ear, where the skin is thinnest, or else their needles won’t penetrate the very, very thick skin.

Caring for their skin is a very involved process for black rhinos. First of all, they can be infested with over 20 species of skin parasite, including ticks and worms, which bite their skin and suck their blood. They can also get sunburns and since they don’t sweat, they overheat easily.  Rhinos deal with these problems in a number of ways. The first is wallowing. Rhinos will roll around in mud to cool off and when it dries, it protects their skin from sunburn and parasites. However, baby rhinos won’t go into the mud wallows until they are big enough to climb out and nursing moms won’t go in everyday, probably to keep close to her baby and to keep her teats clean. This is just one of the many sacrifices a mother rhino makes for her young. However, they will roll around in dust.

rhinos

Apparently, mom's sacrifices don't go unappreciated. Image given to me by the San Francisco Zoo.

Another thing black rhinos will do for skin care is rubbing, which also helps get rid of parasites. They will often use the same rubbing sites for generations and favorite rubbing posts can become practically polished over time. But, all the rubbing and wallowing won’t help them in one particular spot. They can’t quite reach behind the “elbows” of their front legs and rhinos frequently have sores there that can sometimes get infected.

Rhinos also have helpers in their skin care. The most well known is probably the ox-pecker-a neat little parasite eating bird.

oxpecker

An ox-pecker perched on a branch. Image taken at the Oregon Zoo.

These birds will climb all over a rhino and pick at its skin, ears and nostrils and of course, the rhino doesn’t bother them. When ox-peckers feed on antelope, they will take little bits of fur to line their nests, but when they feed on rhinos, all they get is the chance to eat parasites. Still, that’s sometimes enough for them. These ox-peckers will also fly and squawk loudly when danger is near, so they are also a good alert system for the rhinos as well. (While most full grown rhinos have nothing to worry about, lions will sometimes catch older or sick rhinos and calves are always at risk-1 in 6 rhino calves die in their first two years of life. Hyenas are often the cause because they can team up to get around mother rhinos who will aggressively defend their calves.) Unfortunately, ox-pecker numbers have seriously declined in southern Africa because farmers have been using pesticides on farm animals and the birds die from eating poisoned ticks on domestic cattle. The good news is that the birds are now being reintroduced in areas where pesticide use has been reduced.

Perhaps a more surprising rhino helper is a terrapin, a shelled animal closely related to turtles and tortoises. The terrapins live in waterholes where the rhinos wallow and then pull ticks from the rhinos’ skin underwater. Dung beetles also help rhinos, in an indirect way. Remember those sores behind the rhinos’ front legs? A particular parasitic worm loves to dwell is that little safe zone and this worm reproduces in the rhino’s dung. When a dung beetle carries the dung away, it takes the worms away with it. So rhinos have a few helpers to maintain their beautiful skin.

Another feature some rhinos have is a prehensile or partially prehensile upper lip.

A greater one-horned rhino, Gauhati, extending his prehensile lip to receive a carrot. Image taken at the San Francisco Zoo.

This is what Gauhati, the San Francisco Zoo’s greater one-horned rhinoceros looks like with his prehensile lip extended. Here’s what he looks like once he’s pulled his lip back in:

Gauhati

Gauhati after receving a carrot from my husband, Trey. Image taken at the San Francisco Zoo.

Rhinos will pull down branches with their horns and use their prehensile lip to grab twigs and leaves and twist branches until they break. Pretty much any form of bush or shrub within reach is food for a rhinoceros, right up to the thorniest acacia. After a fire on the open plains, rhinos have even been observed eating wildebeest dung, possibly because they were short of the minerals they needed or maybe because they couldn’t find any other food and wildebeest don’t digest grass well.

black rhino

A black rhino at the San Francisco Zoo.

The last rhino feature I’m going to mention is the cause of death for many, many black rhinos. I’m speaking of course of their horn. Rhino horns are made out of compressed hair, but are still incredibly strong. Charging rhinos can poke a hole through a car door. Various cultures have different uses for rhino horn, including for use in traditional medicines or as dagger handles (thanks to education programs, this practice is becoming increasingly rare in Yemen) and since rhino horn is a real status symbol, people pay a small fortune for them. You might recall in a previous post about poaching I mentioned that poachers have high end technology, including helicopters and night vision. If we’re to prevent this animal from going extinct, we have to arm their guardians with advanced technology as well and continue education programs in countries where rhino horn is used. The poaching won’t stop as long as it is such a lucrative industry.

If you would like to help rhinos, there are a number of organizations that you can donate to that provide for rhino rangers, anti-poaching units, equipment for monitoring rhino populations and for breed and release programs. The International Rhino Foundation is a great one. One of the easiest things we can do and my personal favorite is an annual fundraiser put on by the American Association of Zookeepers. It’s called Bowling for Rhinos, and 100% of the profits gets dispersed among various reputable rhino conservation organizations. Follow that link and you can learn where Bowling for Rhinos is taking place near you; enjoy bowling, pizza and friends while saving rhinos. It’s a lot of fun.

 

emperor tamarin

An emperor tamarin with his tongue against the glass. Image taken at the San Francisco Zoo.

So one day last summer, I was cruising around zoo grounds at the San Francisco Zoo and of course I stopped to check on the emperor tamarins. These small primates always have twin babies this time of year and I enjoy watching them slowly growing up, from clinging to their parents’ backs to learning how to climb and jump across their exhibit. Most of the time they ride on their father, who is pretty possessive and only gives them up to their mother for nursing. At any rate, while I was watching the tamarin exhibit, I noticed some odd behavior from two of the monkeys. They were competing for the position on top of this stick and when they were there, they were doing things like in the picture above. Here’s a couple more pictures of what was happening:

 

Emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

What were these silly monkeys up to? I discovered the answer. Take a look at the next pictures and see if you notice it too.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

emperor tamarin

An emperor tamarin. Image taken at the San Francisco Zoo.

Clearly, these two tamarins were pining over that huge, yummy crane fly on the wall just outside of their exhibit. Perhaps trying to will it closer with the power of their minds. Or maybe…”if I just look at it this way, I’ll see the way to get it.”

Reindeer

Belle and Velvet (background) endlessly grazing in their temporary home at the San Francisco Zoo.

My very first zoo job was “reindeer intern” at the San Francisco Zoo, where I had cool reindeer artifacts and talked to zoo patrons about our beautiful antlered guests. The most common conversation I had went something like this:

Guest: So what are these guys?

Me: Reindeer.

Guest: No, what are they really?

Me: Reindeer.

Guest: No, I mean I know you’re doing the Christmas thing and they have muzzles, but what type of deer are they really?

Me: Reindeer.

Guest: Wait, there really is a such thing as reindeer?

Me: ??

It was actually pretty awesome for me to show them that at least one Christmas fantasy was real-except they don’t fly (yet).

So, reindeer are in fact real. They were domesticated from caribou and are considered a subspecies. There are a few differences between reindeer and wild caribou, but the most obvious one is size-reindeer tend to be about a foot shorter than their caribou cousins.  In a genetic study of Alaskan reindeer and caribou, there were significant differences between these two groups of animals, so although they are capable of breeding with each other, little genetic exchange has occurred.

Holly

Holly had a part of her antler that stretch out in front of her nose. When she lifted her head from a food bin, she frequently brought a lot of hay with her. Image taken at the San Francisco Zoo.

Holly

Holly was also a master at getting her muzzle off. Image taken at the San Francisco Zoo.

They were domesticated for milk (yes! You can have reindeer cheese!), fur and meat and it is believed that they were domesticated before horses were.

The other topic that frequently came up was the difference between horns and antlers. Deer have antlers, which means that those great big head adornments fall off and regrow every year! Reindeer are one of the few deer species in which both the males and females have antlers.

In our particular group, we had 4 reindeer. Holly was the dominant one and she was a bully. But we spread the food out and she couldn’t be everywhere at once. Belle was second in command. She used to like to play in the water bowl. The others would sip and leave, but she would hit the inside with her hoof and splash in it. By the time she was done, she would often be soaking wet. Peppermint was the smallest female. She would lounge around in the grass and mostly just tried to stay out of Holly’s way. And then there was Velvet. I think he was most peoples’ favorite. I couldn’t tell you why. Maybe because he was clearly the underdog in the exhibit. Maybe it was the way he slowly ambled around the exhibit instead of bounding around like the others. The way he walked reminded me of Eeyore. Maybe the others thought so, too.  I don’t know, but he won many hearts that Christmas.

On a non-reindeer note, Backyard Zoologist is taking a little holiday break to visit family. Posting will continue on the regular schedule of Mondays, Wednesdays and Fridays on January 3, 2011. Happy Holidays!

rhino kisses

Elly's calf licking his mom's horn. Image given to me by the San Francisco Zoo.

As poachers gain increasingly sophisticated tools, including helicopters and night vision technology, anti-poaching units comprised of police, park authorities and private agencies are struggling in their efforts to protect their charges. SANParks (South African National Parks) has requested military assistance and the military has indicated that they are willing to help. They have exceptional air to land equipment that will be essential in this on going battle. Read more here, but be aware that the related links at the end have some VERY graphic pictures on them.

This picture above is of Elly, the black rhino at the San Francisco Zoo and one of her calves. Elly is part of a conservation breeding program and has the world record for having the highest number of calves in captivity.

Hedgies

Hedgies

An African hedgehog is a great animal for school education programs. Image taken at the San Francisco Zoo.

If you’re ever hanging out with a hedgehog, there are a few things you might notice. Despite their spiky look, hedgehogs are actually smooth to the touch if their spines are relaxed and laying flat against their back. They will usually walk around pretty slowly, sniffing constantly as they go, but if they are scared, they can run pretty fast- up to 6.5 feet per second! Most of the time, if you’re hanging out with a hedgehog, they’re sleeping. They’re nocturnal and African hedgehogs like the one pictured above will sleep 18 hours a day, during active months. Still, the 6 hours they’re awake can be a lot of fun. This little hedgehog likes to run around on her exercise wheel.

Hedgehogs are covered with up to 7,000 spines, which is quite a handy adaptation. Each spine has its own tiny set of muscles to raise it straight up if they are startled or to relax it back down when the perceived threat is past. This reflex is so strong that a European hedgehog in the middle of hibernation (when their heart rate drops from 150 to 18 beats per minute and their temperature drops from 93.2 to 39.2 degrees Fahrenheit) will still raise its spines if they are disturbed, even without waking up. To avoid danger, hedgehogs will also roll up into a ball, with their face hidden by their protective spines. This is quite effective. One of the only predators of the European hedgehog is a badger. The only major predator of the African hedgehog is the Verreaux eagle, which will pick it up in its talons, carry it high in the sky and then drop it to get past its defense.

Their spines are not just for defense. For example, hedgehogs are one of the few animals that can eat adders, because adder fangs are shorter than hedgehog spines, so the hedgies are protected from the adders’ venomous bite. Their spines will also absorb the shock if they climb over an obstacle and roll down the other side.

Hedgehogs are born with their spines, but they are wrapped up under a layer of skin, so they don’t hurt the sow when the young are being born (female hedgehogs are called sows, males are boars and the young are hoglets). Hoglets will recognize their mom by scent. Sows are very efficient reproducers. If their den is disturbed within a few days of birth, the sow will eat her young. It’s actually a very practical thing to do. The young will not survive being moved if they are only a few days old, but if she eats them, then she can gain enough energy to breed again. If the hoglets are over a week old when their den is disturbed, she will carry her young to a new den in her mouth.

In Europe, hedgehogs have a pretty close relationship to their English people-friends. People will frequently leave out bread and milk to attract hedgehogs to their yard because they are very helpful and eat garden pests. They are also very cute and fun to watch. Of course, this state of friendship wasn’t always the case. In 1566, they were considered vermin and a 3 pence reward was offered for every hedgehog killed. The same reward was offered for anyone catching a hedgehog milking a cow, as they were believed to be stealing milk from cows at night. If that sounds crazy to you, I can understand why-these animals are not very large. One thought for why this myth existed is because hedgies are often found near cows because they eat the insects that live in cow dung. Another idea is that in the early morning, cows’ udders are full and sometimes the cows can be found lying on the ground. If they leak, hedgehogs might lap it up. A few years ago, one cow was inspected and had a teat that was damaged in a way consistent with hedgehog teeth. But this is probably not a very common occurrence. Today, far from offering a reward for dead hedgehogs, the law actually states that it is illegal to kill a hedgehog with a machine gun or to catch a hedgehog using a tape recorder. (??? Your guess is as good as mine.)

While I’m poking fun at things people used to believe, in the 1658 book “History of four footed beasts and serpents” by Topsel, the following things were believed to be remedies from hedgehog:

-it cured leprosy

-their dried rib skin would help those with colick

-hedgehog ashes cured boils

-powdered hedgehog skin stopped hair from falling out

-using burning hedgehogs as a fumigant “by God’s help” would cure urinary stones

-a hedgehog’s right eye, fried in linseed oil and drunk from a brass vessel, improved ones night vision and

-hedgehog fat “stayeth the flux of the bowels.”

And with that, I will leave you with one last picture of an African hedgehog:

African hedgehog

An African hedgehog. Image taken at the San Francisco Zoo.

Black-crowned Night-Herons

Black-crowned Night-Heron

A Black-crowned Night-Heron. Image taken at the San Francisco Zoo.

The Black-crowned Night-Heron is one that you are likely to come across if you are interested in birding. Although they are usually nocturnal, they are the most common heron and can be found throughout 5 continents (the missing two are Antarctica and Australia). They are very adaptable birds and are known to eat everything, even garbage and organic refuse from land fills, although they primarily eat fish. In winter time they roost communally and during breeding season they nest colonially, each pair building their large nests in trees with several other pairs. In fact, they are thought to be too abundant by some, particularly owners of fish hatcheries. They like to nest nearby this wonderful abundance of food and are thought of as pests when they do.

Despite being easy to find, if you see a tree with nesting birds, it’s a good idea to admire them from a distance. For one, the young are known to be exceptionally aggressive and will defecate and regurgitate on humans coming to close. (Unfortunately, I was not aware of this when my best friend and I stumbled upon a tree of nesting birds in Chile and let’s just say I was the lucky one.) This is actually quite a fortunate circumstance for scientists who are researching the composition of the birds’ diet. Personally, I have to love those that are so driven by the excitement of answering a question that they’ll enthusiastically dig through baby bird vomit. 🙂 The other reason to steer clear of nesting birds is that despite them often being found relatively near humans, if a human visits a new nest or a recently laid egg, they will often abandon it. If there are frequent visits by human pests, it will also discourage late nesting herons from settling down. So it’s not good for you or the parents-to-be if you’re hanging around.

A Black-crowned Night-Heron

A Black-crowned Night-Heron at the San Francisco Zoo.

Once they do settle into a nest, though, these birds are thought to be monogamous. The male performs a courtship display for the females (who are usually rejected at first) and the female of choice is eventually allowed into the territory, where they’ll preen each other and rub beaks.  You can tell when a happy couple has paired because at the time of pair formation, their legs turn pink! Like most birds, the pair will work together to take care of their young. If other chicks are placed in their nest, say by a mischievous researcher, they will also brood young that are not their own.

Also, not on night herons, but the Belize Zoo was recently hit hard by Hurricane Richard. There was major damage to the facility and they are looking for help to put them back together. There are images of the damage they suffered and a link to make contributions here. This little zoo has rescued many animals and participates actively in research, conservation and education programs.