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About Author: Mike Grue

Posts by Mike Grue

4

Bird Keeper: A Busy Calendar

Blue-winged pittas love their megaworms.

Blue-winged pittas love their megaworms.

The Tiger River “string” is composed of six bird exhibits that line the Tiger Trail above and below the Malayan tiger exhibit at the San Diego Zoo. In these 6 exhibits there are around 120 birds. Normally, the birds are fairly predictable and easy to keep track of. The blue-winged pittas Pitta moluccensis come out of hiding for their tossed megaworms. The Malay great argus male Argusianus argus greets me at the door but expects his peanuts to be tossed deeper into the exhibit. His friendlier mate comes directly up to my shoe for the same thing.

Our nice-and-quiet routine is dramatically altered once their hormones kick into high gear. Starting around March and typically lasting through August or September, the breeding birds behave differently. They find new hiding places to make nests, they need more fruit or bugs added to their daily diet, and they become more territorial. The easy-to-predict birds suddenly become much more unpredictable!

I have my own calendar at my workstation that helps me visualize what is going on in these six exhibits. When I find eggs that I expect to hatch (fertile eggs that are being incubated), I look up the incubation duration for that species and figure out when those eggs should hatch. The earliest date when an egg should hatch is labeled and highlighted in pink. Any approaching pink-highlighted date lets me know I have to get ready for a potential new chick! The actual hatch is highlighted in yellow. Having hatches easily visible and clearly marked comes in handy many times. Expected fledges are noted in blue. These dates are important, because keepers need to know when a chick is expected to leave the nest, as we frequently add low perching or empty a deep pool for the young and inexperienced fliers.

A black-throated laughingthrush parent is kept busy feeding its chicks.

A black-throated laughingthrush parent is kept busy feeding its chicks.

For example, I noticed a pair of black-throated laughingthrushes Garrulax chinensis sitting on a nest earlier in the month and had figured out that April 12 was the earliest hatch date for the egg. Just before expected hatch, I ordered more bugs to go into their exhibit, as laughingthrush chicks eat a lot of insects. But there was a gap of two days before the chick did hatch. I did not go up to the nest and disturb the parents but knew there was a hatch based on the parents’ behavior—they were stacking bugs in their beaks and bringing a mouthful of mealworms, crickets, and waxworms up to their nest!

Usually 12 days after a black-throated laughingthrush hatches, the chick leaves the nest or fledges. A few days before the chick fledged, I put out some shallow water pans and emptied the pool in their exhibit. If the chick left the nest early, I wanted to make sure that it didn’t get trapped in the cold water. But that is not all! In May, I wrote down the date when the chick would be big enough to have an ID band put on its leg.

One last thought. As crowded and as colorful as this calendar can get, the six exhibits on the Tiger River string are not even the busiest breeding exhibits in the Bird Department. There are eleven other strings in the department, and many of them have more going on during this dynamic time of the year! I am humbled by the amount of knowledge my coworkers have and the amount of work they and our supervisors—who have to organize and manage all 12 strings!—put into their jobs. My hat’s off to all of them!

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Food Time!

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Food Time!

The great argus pheasants share their aviary with a variety of birds, each with its own dietary needs.

The great argus pheasants share their aviary with a variety of birds, each with its own dietary needs.

It should come as no surprise to hear that the most interesting, and dynamic, part of the day in any bird exhibit is usually feeding time. Even though our birds have constant access to a nutritious and balanced diet, a keeper entering the exhibit with new food pans means there are usually some choice goodies that any fish-eating stork, mealworm-devouring woodpecker, or grape-gnawing fruit-dove can’t wait to get a hold of. While the scope of a keeper’s entire morning feeding routine may be too overwhelming to cover in one short blog, we can take a look at how exciting feeding time is in one particular bird exhibit at the San Diego Zoo.

The Malay great argus exhibit (just next to the lower tiger viewing glass) is home to a number of colorful characters. At any given moment you may witness the stunning fairy bluebird Irena puella singing his tune while making fast, powerful darts from perch to perch, the mischievous blue-winged sivas Minla cyanouroptera flitting from leaf to leaf, the hooded pittas Pitta sordida hopping in and out of the ground cover on spring-loaded legs. And in the background you may hear the black-throated laughingthrushes Garrulax chinensis and Chinese hwameis Leucodioptron canorum calling back and forth to their mates.

As vibrant and lively as this exhibit is throughout most of the day, things really start to get exciting when the birds hear a keeper approach. Their first clue that it is feeding time is probably when they hear the lock being unlatched. By the time I enter the exhibit, the birds have taken their stations and are ready for their breakfast.

Blue-winged sivas are the smallest birds in the aviary and get fed first.

Blue-winged sivas are the smallest birds in the aviary and get fed first.

When I first enter the exhibit, I am frequently surrounded on three sides with expectant birds. The first to get fed are usually the smallest birds in the exhibit: the blue-winged sivas. These little guys are usually embedded in the nearest foliage, chirping away. They can be hard to find, but when they see me looking for them, they pop their heads out of the foliage and fly out to catch their tossed mealworm. When they both have their breakfast treat, they retire to an upper corner of the exhibit to enjoy their grubs together. Two down, fourteen to go!

The Malay great argus Argusianus argus are usually next. I toss a few peanuts deep into the exhibit. As the male sprints away to hunt down his peanuts, I drop a couple at my feet for the female and her chick to enjoy.

By this time, the male white-rumped shama Copsychus malabaricus is growing impatient, and he is perched about 3 feet in front of my chest, staring straight at me. I toss a few waxworms (moth larvae that look like large maggots—not as gross as it sounds!) into the crook of the tree behind him. The voracious male usually inhales all the insects within reach. Though if he has chicks he is feeding, the male stacks as many bugs into his tweezer-like bill as he can before flying off to care for his chicks.

If I have timed the feeding right, the argus mom and baby have just finished their peanuts and are moseying over to their morning sun bath when the pittas hop over to my feet and declare they want their food—now! A reclusive species notorious for their solitary habits, pittas can fight over their food if they think their mate unfairly stole their worm. By tossing one redworm to my left and one to my right, the pittas about-face and hop to opposite ends of the exhibit, where they can enjoy their treat all by themselves.

After the fairy bluebird catches his third bug in mid-air, and the female shama has darted out from her ground cover to snag a forgotten cricket, the excited mob of birds thins to a mere congenial gathering. This is when the patient laughingthrushes and humble hwameis emerge to land on nearby perches. I toss a few bugs into the leaf litter and let them hop down to kick up their own food. As I finish setting out the morning food pans, I usually leave the exhibit to the pleasant, rhythmic sound of the laughingthrushes and hwameis kicking leaves, tossing twigs, and digging in the dirt in their search for that last, elusive grub.

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, His and Her Massages: Collared Lories.

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His and Her Massages: Collared Lories

Collared lories

Collared lories engage in allopreening.

A bird has many good reasons to make sure its feathers are in top condition. If the feathers become dirty, oily, shabby, or broken, the bird may have trouble keeping warm, attracting a mate, or even flying! This is why it is not uncommon to see a bird spend a good portion of its day grooming—or preening—itself. When birds preen each other, it is known as allopreening. Many species do not allopreen. They may sing for hours to woo a potential mate, perform stunning visual displays to communicate their intentions, or may share their food to prove what a good mate they would make. But when it comes to taking care of the feathers of their friends or mates, forget about it!

However, there is group of birds that is very well known for being faithful allopreeners. I still stop and watch anytime I see a pair of birds delicately grooming the feathers around their mate’s eyes or ears (birds have ear holes exactly where you would expect to find them—they are just well covered by feathers). Frequently, the bird receiving the massage has its eyes closed and head cocked to the side. I can’t imagine the bird enjoys it any less than we humans!

Oh, that feels good!

Oh, that feels good!

This month I saw a pair of collared lorries Phigys solitarius start out preening in an adorable—and common—way. The male was being groomed and had his eyes closed, letting the female preen all around the side of his face. While watching the pair, I saw that the moment the female stopped preening the male, he immediately started to preen her…for a few seconds. He stopped, she started…for a few seconds. She stopped, and he started. They went back and forth like this every few moments for a couple of minutes. After being enthralled by this display, I realized that this was my blog subject for the month! Luckily for me, the birds continued their display long enough for me to get some good video.

I was standing on the public walkway when I saw these two lovebirds, so the video below was taken looking through the visitor viewing just across the sidewalk from the fishing cat along the Tiger Trail at the Zoo. The video is not as unobstructed as I usually try to share with you, but I think it is cool that you don’t need to be a zookeeper to witness this adorable display of affection…just some good timing!



Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, A New “Tree” for Woodpeckers.

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A New “Tree” for Woodpeckers

A yellow-naped woodpecker is hard at work.

A yellow-naped woodpecker is hard at work.

Nothing beats natural behavior. Allowing birds to use their evolved traits, behaviors, and abilities usually results in a healthier bird in both mind and body. We encourage natural foraging behaviors by hiding earthworms in loose soil for the kiwis to hunt. We do bug scatters in the diving duck aviary for the ducks to dive for (it is so cool to watch!). And we try to make available various nesting material the birds would look for and use in the wild. Hummingbirds get spider webs, weavers get thorny twigs, and woodpeckers get…hmm…how do you replicate the tall, thick, dead trees most woodpeckers prefer to use in the wild? The San Diego Zoo’s Horticulture department does such a good job at keeping the trees alive and healthy that there are not many dead trees available. Not to mention that it would be difficult to actually move those trunks into the exhibit!

Enter the cork nest! The ingenious box was developed by curator Peter Shannon and his team at Albuquerque Biological Park. The nest box has plywood sheets on the top, bottom, and three sides. The fourth side is open, exposing the cork. The idea is that the cork is hard enough to provide the birds a tough substance to chip away at but is soft enough for them to still make progress. Here’s a photo essay and video of what happened…

On February 3, 2014, I used a tool to make a small indent in the hard cork on the front of the nest box and installed the box in the yellow-napped woodpecker’s Picus chlorolophus exhibit, which is just up the hill from the turtle exhibit on Tiger Trail.

#1: On February 3, 2014, I used a tool to make a small indent in the hard cork on the front of the nest box and installed the box in the yellow-napped woodpecker’s Picus chlorolophus exhibit, which is just up the hill from the turtle exhibit on Tiger Trail.

Within hours, the male was clinging to the front of the nest box and was working away at the starter hole I had made! You can see that the woodpeckers are much better at making circles than I am…how embarrassing.

Within hours, the male was clinging to the front of the nest box and was working away at the starter hole I had made! You can see that the woodpeckers are much better at making circles than I am…how embarrassing.

After congratulating myself for thinking about making the starter hole, I walked into work on February 9 to see this. Hmm, obviously I didn’t put the starter hole in the right place and the birds had come up with their own location.

After congratulating myself for thinking about making the starter hole, I walked into work on February 9 to see this. Hmm, obviously I didn’t put the starter hole in the right place and the birds had come up with their own location.

By February 16, though, the birds had come up with an even better spot!

By February 16, though, the birds had come up with an even better spot!

 A week later, the three holes look like a surprised cork ghost...

A week later, the three holes look like a surprised cork ghost…

 ...and by March 16, a scared cork ghost!

…and by March 16, a scared cork ghost!

It has been such a joy these past few weeks to see both of the woodpeckers engaging in their natural nesting behavior. At the time of this writing, the bottom hole is the most extensive cavity that reaches to the very bottom of the nest. The upper right hole is also large but does not extend or break through to the bottom hole. And the top center hole—the one I helpfully started for them—nothing. I think they just worked on it to be nice.

The video below is not the up-close-and-personal video I’ve tried to show in the past. But I think it is great in that it was taken from the guest walkway and is exactly what observant—and lucky—guests might be able to see for themselves! In the video, the woodpecker is “corkpecking” and chipping away at the material. Later in the day, I was delighted to see the female’s pointy beak emerge full of loose bits of cork. She spat the cork out, ducked back into the nest, and emerged seconds later with another mouthful of excavated cork. How cool!

Woodpecker Video

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, A Trick up Her “Sleeves.”

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A Trick Up Her “Sleeves”

What tricks did this bird have up her "sleeves"?

A male blue-crowned hanging parrot has a red “bib” whereas the female does not.

I never stop learning at the San Diego Zoo. It is one of the best things about working here! I am constantly challenged to learn more about the birds I work with, the exhibits I work in, and how I can take better care of both. Sometimes I learn technical skills like how to install a mister system that can be utilized to give the birds a bath. Or I can read up on tips to successfully breed red-billed leiothrix Leiothrix lutea. Many times I learn from simply observing the birds go about their daily routines.

A few days ago, I was doing an end-of-the-day check on the blue-crowned hanging parrots Loriculus galgulus just up the hill from the tiger exhibit. As I was getting a head count, one of the birds caught my eye. It looked like one of the adorable little females had done something to her primary feathers. It seemed as if she had lost some of the barbules at the tips of her long, green feathers; it made her back look spiky. She was perched on a palm frond, chewing on a leaflet, and didn’t seem to be concerned with her odd feathers. After a few moments, she quickly flicked her head back to preen the spiky feathers and then returned to her chewing. A few more moments, another quick flick and preen, and back to the frond.

It's easy to see how the blue-crowned hanging parrot got its name!

It’s easy to see how the blue-crowned hanging parrot got its name!

It was after the third or fourth flick that I started to suspect what the tiny parrot was doing. My first reaction was that I must be imagining it—she surely wasn’t doing what I thought she was doing, was she? I had never heard of such a behavior, and I couldn’t believe she was being so smart…so efficient.

I crouched down in front of the exhibit to get the best vantage possible. I stopped watching her quick flicks, chewing, and preening, and instead focused on her spiky back. With a quick movement, the female turned her head, preened, and went back to her work. But there was a new spiky green “feather” in her back!

She wasn’t preening broken feathers after all! She was snipping little bits off the palm frond, sticking the cuttings onto her back, and using her feathers to hold them in place! I knew these little parrots lined their nests with strips of plant material, but I had never envisioned them using their back feathers as a type of backpack. With only one trip from her nest, this female was able to bring back over half a dozen strips to her nest instead of the paltry one strip she could’ve brought back if she had carried it in her beak.

This behavior has been documented before, but it is not something seen on a regular basis. Indeed, after eight years working with birds, I had never even heard of it. It makes me excited to find out what other tricks these birds have up their sleeves…er, feathers.

Mike Grue is a senior bird keeper at the San Diego Zoo. Read his previous post, Sing, Song.

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Sing, Song

Listen to the red-billed leiothrix's song!

Listen to the red-billed leiothrix’s song below!

Birds can make some of the most beautiful music in the world. The sweet call of the northern cardinal Cardinalis cardinalis tells us spring is coming. The majestic cry of the red-tailed hawk Buteo jamaicensis evokes a sense of being connected to nature—the sound most movies incorrectly play when they have a bald eagle Haliaeetus leucocephalus on the screen. Loons sound so lonely and remorseful, it can make the heart ache. While those sounds evoke a variety of emotions in humans, birds sing and call for different reasons. Sometimes they may sing to announce their territory, to communicate with their mate, or to attract a mate in the first place.

The San Diego Zoo’s beautiful pair of red-billed leiothrix (pronounced LY oh THRIX) Leiothrix lutea in the enclosure just up the hill from the tigers take singing to the next level. The male has a wonderful repertoire of warbling whistles. He has so many notes, and it varies so much, it sounds like a new song every time he sings. To start the duet, the male spends about ten seconds delivering a gorgeous song before he takes a break. Then it’s the female’s turn. In the pause after the song, the female utters a low-pitched chirp, chirp, chirp, chirp. That’s it! Following the female’s contribution, the male picks right back up with another round of lovely notes. Once he finishes…chirp, chirp, chirp, chirp. Another song…chirp, chirp, chirp, chirp.

red-billed leiothrixAt first I couldn’t tell exactly what was going on, but after listening for awhile I noticed a few things:

1) The female never interrupts the male mid-song; she always waits until he is done to deliver her chirps.

2) The female chirps three to five times—with four being the most common.

3) The male starts his song again after her chirps, but waits for her chirps before he starts up again. This became obvious when I heard him finish his song, but the female didn’t call back right away. She was delayed because she was eating and had just swallowed a large piece of fruit! The minute she could, she chirped to complete her end of the duet.

Why does she chirp? Why does the male seem to find her call so important? I don’t know. I haven’t found any literature to suggest that they are actually “duetting” in the formal sense of the term. But when both of the birds seem to take their cue from each other, I think the term is appropriate. Either way, it is extremely interesting and quite cute!

Check out this vocal pair of birds uphill from the tiger exhibit (just next to the turtle exhibit on Tiger Trail).

 

On the audio, we first hear the male producing a short song followed by the female’s lower pitched, encouraging chirps. They continue back and forth for some time with the longest and most impressive song at the end of the recording. The female chirped anywhere from seven to ten times between the male’s song. This is a higher number of chirps than I had heard earlier in the month. I wonder if the female chirps more as the pair gets closer to the breeding season? Something to look forward to listening for as winter passes and spring starts to round the corner.

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Pick on Someone Your Own Size!

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Pick on Someone Your Own Size!

A Reichenow's weaver gathers nest material.

A Reichenow’s weaver gathers nest material.

Valentine’s Day may be tomorrow, but the birds at the San Diego Zoo are already wooing their sweethearts, and I’d like to share a story about a brave male weaver sticking up for his shy girlfriend.

Reichenow’s weavers Ploceus baglafecht reichenowi aren’t known for being aggressive birds. They are small, black-and-yellow birds with great personalities and have a tendency to get along with all their roommates. That’s why I was surprised to see the San Diego Zoo’s male Reichenow’s weaver (in the African aviary between Scripps aviary and the gorilla exhibit) get into a disagreement with an oriole warbler Hypergerus atriceps. When I explain why he told off the larger female oriole warbler, you may think that he was only being fair….

At the time of the incident, the oriole warbler had only been in the exhibit for a few days. During her introduction into the exhibit, she had established a few favorite perches. One day the weaver female accidentally flew to one of the oriole warbler’s favorite perches right when the oriole warbler was trying to land there! They landed on the branch at about the same time, and the warbler scolded the weaver female. Sternly squabbled at, the weaver immediately flew to a neutral perch and seemed to be content to let the matter rest. Her mate was not!

An oriole warbler is the new bird on the block.

An oriole warbler is the new bird on the block.

The scolding oriole warbler must have attracted the male weaver’s attention, because he launched himself across the aviary, landed next to the startled warbler, and gave her the same scolding she had given his mate moments earlier. The warbler instantly backed down and flew off, leaving the male weaver to fly over to his mate to make sure she was okay. I kept an eye on this trio for the next few days and saw that everyone was getting along and had easily moved past the misunderstanding.

I think we could draw a number of funny, anthropomorphic tales from this interaction, but I do think that the weaver female hadn’t meant to anger the oriole warbler, which possibly overreacted due to being a little nervous in an unfamiliar aviary. And I do think that the weaver male was absolutely sticking up for his mate.

Interesting how much humans have in common with 1.5-ounce birds, isn’t it?

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post,

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Hands Up: You’re Surrounded!

Two members of the white-faced whistling duck gang

Two members of the white-faced whistling duck gang

The white-faced whistling ducks Dendrocygna viduata in Scripps Aviary at the San Diego Zoo are not known for being shy. They are not known for being subtle. They are not known for being quiet. What they ARE known for, by their keepers at least, are their ambushes and shakedowns!

The bird keeper working in Scripps Aviary has a morning filled with sights and sounds. The African grays Psittacus erithacus whirl, and caw. The green woodhoopoes Phoeniculus purpureus constantly cackle. The emerald starlings Coccycolius iris chirp, and the great blue turacos Corythaeola cristata make whatever crazy noise they make. Amid this beautiful symphony of sound, a keeper may forget to keep an ear out for the whistling duck gang.

The ambush starts off with an innocent high-pitched chirp. The chirp alerts those in hiding that their target is near. In moments, the whole flock of white-faced whistling ducks has the keeper surrounded! Whistling at the top of their small but mighty lungs, the ducks close in. The only way out of the jam? A quick-thinking keeper can distract them by tossing a couple of millet sprays into the water. Once the ducks take the bait, placing their food pan near their pool is another way to ensure that the keeper will be allowed out of the trap in one piece.

Okay, maybe I am being a little over-dramatic. The ducks are fairly friendly and never attack their keepers. I do think, however, that the message they are sending is clear: We want our food!

Check out the video to see what it looks—and sounds—like to be caught out in the open by the whistling duck gang!

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, A Peacock Named Shameless.

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A Peacock Named Shameless

Shameless basks in the sun.

Shameless basks in the sun.

We all have our routines. Some of us wake up and walk the dog around the same block in the same direction year after year. Others visit Starbucks every weekday for their first (or second) cup of coffee of the day. These routines lend predictability to the day and usually make us feel comfortable while doing them.

I’ve learned that when taking care of animals, it is helpful to make a plan and then toss the plan right out the window! The animals don’t care what a keeper’s agenda is or what we planned to do that day. The birds I work with frequently add excitement and unpredictability to my “routine.” Come late morning, however, one particular bird can be counted on to follow a set pattern.

When it comes to patterns, no routine is more comforting than the one between keeper and Shameless, one of the Zoo’s Indian or blue peacocks Pavo cristatus. Please know that the Zoo’s Indian peafowl (peacocks and peahens) roam the Zoo grounds at their pleasure. They do not have an enclosure or aviary. Shameless earned his name because he begs for food without any shame! The routine between bird keeper and Shameless goes like this:

• Around 11 a.m., Shameless shows up to the Tiger River keeper kitchen. He pokes his head through the door and lets us know that “it’s time.”
• The bird keeper takes a pan filled with peacock food out to the courtyard.
• Shameless eats all the crickets, his favorite food, from the pan. He returns to the kitchen to proclaim he is out of food.
• The keeper knows he has plenty of food left and refuses to add more crickets.
• Shameless goes back to his pan to eat the rest of his food.
• Shameless then walks back to the kitchen door and rests on his side in a sunny spot directly outside the kitchen door.
• The keeper pretends to be annoyed that the door is blocked and shoos him away.
• The keeper is secretly pleased that Shameless will be back the next day, and the next…and the next.

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Hornbill Family Feeding.

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Hornbill Family Feeding

Trumpeter hornbills are native to Africa.

Trumpeter hornbills are native to Africa.

I took video (see below) of the San Diego Zoo’s trumpeter hornbill Bycanistes bucinator family catching mega-worms, the larval phase of a species of beetle. These omnivorous birds enjoy eating: apples, grapes, papaya, figs, yams, mealworms, crickets, and waxworms. But their favorite food items are the mega-worms I’m tossing in the video.

The bird with the largest beak nearest to the camera at the beginning of the video is Dad. The other birds in the video are his two daughters and one son. Mom is in the exhibit, but she is off camera enjoying a rare moment of peace from the barrage of attention her mate and youngsters constantly crave.

What I really like about this family is just how well they get along. The two females in the video hatched last year, and they have helped to raise their younger brother, who hatched this year! This behavior is not unusual for this species, as they are cooperative breeders, meaning the young from one clutch help their parents raise the next clutch. They share food so well that toward the end of the clip, one of the females actually takes the mega-worm out of the Dad’s beak. He doesn’t scold or chase after her but instead waits patiently for the next bug to be tossed (notice that I do make sure to toss him the next one).

Did you notice the way the hornbills chewed their food before swallowing? Check out the video again to see the way the birds deftly manipulate the bug before they swallow it. Mega-worms have an exoskeleton that can be harder to digest than most food items. To help ease the process, the birds “chew” their food before swallowing.

If you want to say hi to Mom, Dad, and the kids, you can check them out near the meerkat exhibit in Africa Rocks.

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Pelican Keeper Chat.