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About Author: Mike Grue

Posts by Mike Grue

3

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.

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Pelican Keeper Chat

The great white pelican is an impressive bird!

The great white pelican is an impressive bird!

If you have recently visited the San Diego Zoo, you probably noticed four new additions to the African Marsh exhibit across from Eagle Trail. These new birds may be young (a little over one year old), but they are hard to overlook. Often eliciting surprised gasps from visitors when seen up close, these bold birds quickly make a grand impression. Yes, the two male and two female great white pelicans Pelecanus onocrotalus are the source of many visitors’ questions. To find answers to some of those questions, I sought out Amelia Suarez, one of their keepers, and had a chat with her about those prodigious pelicans.



Whose idea was it to get pelicans for the African Marsh exhibit?

During a conversation I had with our bird curator, I asked if we could get a few pelicans for the Zoo’s African Marsh exhibit. I love pelicans! When I used to go to La Jolla Cove, I would see the cormorants and pelicans living next to each other. And while the cormorants and pelicans we have in southern California are not the same species as the ones we have at the Zoo, I thought they would go nicely together.

Do the pelicans have different personalities?
Definitely! They are all young, so they frequently act like curious kids and play with anything new. Three of the pelicans are hand raised, but one of the females was raised by her parents. She came to the Zoo very shy and didn’t want to come close to me during feeding sessions. She has since gotten over most of her cautious behavior and now politely takes food from my hand. She even vocalizes to me to let me know she wants her fish.

What preparations did you do before they came to the Zoo?
The biggest thing we did was to add some palm stumps to the exhibit for them to perch on. Most of the work we did was after they were introduced. We cut some vegetation back to make space for them to hang out. And they were so curious about visitors that we put up a perimeter fence and added a number of plants to keep them from getting too close to our guests.

What did the birds in the African Marsh think of their new flock-mates?
The saddle-billed storks weren’t thrilled with them initially. They had a long-established territory, and they didn’t want other large birds to push them around. There were a couple of mild spats between the two species, but the storks have since calmed down quite a bit, and they usually slowly move to another part of the exhibit when the pelicans are on the move.

The cormorants, on the other hand, tolerate them unless the pelicans get too close to the tree where they have their nests, and then the cormorants get agitated and—in unison—bark and warn the pelicans off.

Is feeding in that exhibit any different now?
For their size, they don’t eat much—just one or two large trout per feeding. (Note: depending on the time of year there are two or three feedings per day.) It just means a few extra fish in the bucket. Oh, and of course they want to be the first ones to eat, so the cormorants and storks have to wait their turn!

Do you have a favorite among the pelicans?
All four are my favorite! The males like to pick up fish and fling them halfway across the exhibit. They also help me clean by biting the handle of the rake or brush while I’m using it. The females are sweet; one runs up and leans on me when I enter the exhibit.

Do you have hopes to breed these birds?
We do hope that they will breed once they are sexually mature. I can see the parent-raised female being a good mom if she can attract the attention of one of the males.

What is one thing people would be interested to know about the pelicans that they may not know just by looking at them for a few minutes?
How big they are! I know that anyone can easily see that they are big birds, but when I’m standing next to one of the males, and he is flapping his wings, I realize how truly huge these birds are! (Note: A great white pelican’s wingspan can be over 9 feet!)

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

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Australian Bird Keeper Chat

Dollarbirds are a new species for Jackie to work with.

Dollarbirds are a new species for Jackie to work with.

In May 2013, the San Diego Zoo unveiled its newest exhibit, the Australian Outback. Upon entering the Outback, guests can visit with a number of birds from Down Under including laughing kookaburras, chirping starlings, boisterous dollarbirds, and curious palm cockatoos. The bird exhibits are certainly striking, but to get a behind-the-scenes look at these impressive habitats, I chatted with Jackie Cosgrove, a senior keeper working with the birds in their new digs.

The exhibits look great from the outside looking in. What do the birds think of their new homes?
The aviaries are wonderful. They are long, wide, and tall. There are plenty of perches of various heights, large pools for bathing and drinking, and niches where each species or individual can carve out their own space without having to displace other birds. As a result, there is very little aggression that we’ve seen between the birds. It seems as if the birds are enjoying themselves in their new exhibits.

How can you tell that a bird is comfortable or enjoys its new exhibit?
I look at how the bird flies around the aviary, how it goes to food pans and pools without getting displaced by other birds. I watch the birds utilize the whole aviary freely without becoming flighty when I enter to service it. I see shy birds that have a place they can go to relax and have time to themselves before coming back out to interact with their flock mates.

Our new squatter pigeons are raising chicks in the new Australian Outback aviary.

Our new squatter pigeons are raising chicks in the new Australian Outback aviary.

Sometimes getting moved into new exhibits can delay a bird’s desire to breed as it gets used to its new surroundings. Have you noticed any delay with these birds?
Not really! We had doves mating the day they moved in and finches that were building nests the next day, on eggs a week later, and are now feeding chicks! We even have a pair of squatter pigeons Geophaps scripta (see photo above) that came from another zoo where they never got along but are now taking care of two young pigeons! The female shows them around and the male watches protectively over his family.

Have you worked with most of these species before?
Many of them are new species for me. I’ve worked with squatter pigeons, metallic starlings, and bowerbirds before, but I’ve never worked with finches, dollarbirds, woodswallows, or honeyeaters. It’s been great learning about the many new species!

What has been the biggest challenge for you when working with the finches?
The sheer number of them! When I look up, I sometimes see a swirling cloud of finches: it’s impossible to get a full count.

Can you use your bird husbandry knowledge for all birds?
There are things like monitoring a bird’s health that are consistent throughout most species: alert eyes, good body posture, and healthy feather condition. However, there are some quirks that vary from species to species. Some finches prefer nesting in dense brush, others build nests in a tree cavity. That’s why I talk to bird keepers in other areas of the Zoo who may have experience in working with species that I’ve haven’t.

The tall, dark, and handsome palm cockatoos are a sight to see!

Tall, dark, and handsome palm cockatoos are a sight to see!

Is there one species you especially enjoy working with?
I’m kind of partial to the dollarbirds Eurystomus orientalis because they are so bizarre. But I also love the palm cockatoos Probosciger aterrimus; they are sweethearts. They are kind birds, but they are so extremely smart. We can encourage natural foraging behaviors by hiding food all around their exhibit, but they are so bright and sensitive to their surroundings that it is a challenge to keep them occupied and busy throughout the day.

What is one thing you’d like a visitor to know about your bird exhibits that they may not already know?
One thing I’d want everyone to know about any bird aviary is that you need to stop…and look. You’re not going to be able to appreciate the birds just by walking by and looking. You have to stop and take your time. It’s worth it!

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Favorite Moments: Partridge Family Snackers.

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Favorite Moments: Partridge Family Snackers

A male crested wood partridge has dark plumage while the female is mostly green.

A male crested wood partridge has dark plumage while the female is mostly green.

This story focuses on a video I captured while going about a normal work day as a bird keeper at the San Diego Zoo. It has to do with parents teaching their young how to eat. I think it would be best to watch the video below first and then read the blog. But it is, of course, entirely up to you.

If you have already watched the video of the crested wood partridges Rollulus rouloul eating, you are still probably “cooing” over just how adorable their chick is as it tries to eat anything Mom and Dad pick up. If we look closer, though, we see a number of amazing things that are happening.

The first thing that I just love is that the male is helping to feed the chick. Sometimes it is normal for a male bird to help feed his young, but when it comes to many ground birds like chickens, grouse, pheasants, monals, etc., the males usually never even meet their offspring. Crested wood partridges are quite different: Dad may not help to incubate the eggs at all, but he is a stellar dad when it comes to taking care of his chicks.

At the video’s start, Dad (with the red mohawk and red around his eyes) and Mom are passing a waxworm back and forth while quietly making a vocalization that says something close to “here is food.” We then see the chick suddenly run up to join his parents on the wooden bridge (temporarily set up to span the waterway while the chick is learning how to navigate the exhibit).

A young ground bird doesn’t know what is good to eat, but it is born with an instinct to try to eat anything its parent picks up and makes a fuss over. The bigger the fuss, the more the bird will want to eat the item. What almost looks like teasing from the parents as they pass the waxworm back and forth is really intended to give the chick practice hunting bugs that may not be as easy to catch once the bird has to fend for itself. What a great little family!

Mike Grue is a senior keeper at the San Diego Zoo. Read his previous post, Favorite Bird Moments: We Want a Bath.