Invasion of the bulbuls: Houston team studies new invasive species

Editor’s note: This blog post is a summation of “Ecology, Behavior, and Reproduction of an Introduced Population of Red-vented Bulbuls (Pycnontus cafer) in Houston, Texas,” written by HMNS Curator of Vertebrate Zoology Daniel M. Brooks and published in The Wilson Journal of Ornithology.

 

Invasive species are (unfortunately) nothing new to Texas. Defined as an “introduced species that adversely affect the habitats and bioregions they invade economically, environmentally, and/or ecologically,” invasive species (aka invasive exotics or exotics) can have wide-ranging negative impacts on regions.

Species such as giant salvinia, feral hogs, zebra mussels and nutria constitute invasive species currently wreaking havoc on Texas wildlife, having decimated food sources and changing ecological dynamics, and even threatening other species’ survival in their environmental niches. It’s for this reason that many scientists have begun to study introduced species and their behaviors before they decimate their new habitats.

In light of this, Brooks initiated the Texas Invasive Bird Project in June 2008, a citizen-science study targeting six avian species invading the state. One of these is the red-vented bulbul (Pycnonotus cafer). This species was previously unstudied in Houston.

The red-vented bulbul is native to Pakistan, India, and Sri Lanka, but has become a well-established invasive species in parts of the Middle East, various tropical Pacific islands … and Houston. In its native and introduced regions, it can be found in a variety of habitats, including urban gardens. In the Houston study, we aimed to determine the ecology, behavior and reproduction of the bulbul through a questionnaire made available at birdwatching clubs, annual birdwatching festivals and circulated on internet list serves. Most of the respondents were either birdwatchers familiar with bulbuls or horticulturalists who maintain diverse gardens.

The results determined that the most frequent activities for the birds included foraging, perching or resting and calling. Ninety-six percent of the reports described residential suburbs as the primary habitat of the birds, with the highest concentrations being found in the Heights neighborhood. In these areas, they were observed perching on 35 species of plants, and feeding on 20. Forty-three percent of the plants they perched on are native to Texas, while only five of the 20 plants they fed on are native to Texas. The most common plants used for perching were also exotic plants (bamboo, crepe myrtle, fig and tallow), which are all found in the native range of the bulbul.

They are generally non-migratory birds. But the largest flocks appear at regular intervals between August and September, and then again from December through January, traveling in flocks of 12 to 22 birds. This matches their patterns in other regions, while their numbers are much smaller in Houston (with gatherings of 20 to 100 birds within their native range).

Ultimately, it seems that bulbuls are not currently a threat to Houston, but they should continue to be closely monitored. While they pose no current negative economic threat as they do in Pacific islands (such as Oahu, where they’ve decimated tropical plant crops), it seems that their largest potential threat in Houston remains through seed dispersal. In this area, they have great potential to disperse noxious weedy seeds, as they have done in Fiji with spiked pepper, guava, and prickly night-shade.

In the meantime, the birds seem to be enjoying their niche in previously untapped resources of other exotic plants brought to Houston and used in gardens, which other birds have not used with great regularity to eat or perch in. However, as the population continues to increase and spread through the region, we will have to monitor any changes that may occur which could negatively impact native species.

Just Another Day at the Office

Working in the museum’s permanent collections I focus on artifacts and specimens – after all, that’s my job.  But it’s not just the artifacts and specimens that tell a story around here.  It’s the people too.  Behind all the exhibits and public areas are many folks hard at work to make science and this museum relevant and memorable to you.

Lately, thanks to a recent staff luncheon given by the HMNS Guild and some quick conversations in the halls, I’ve been able to get caught up with my colleagues to find out what they doing behind the scenes.

In my own home department of Collections, Dr. Dirk Van Tuerenhout recently gave a lecture on the Birth of Christianity exhibit in the IMAX. (You can read blog posts by Dirk here.)

Dr. Dan Brooks just co-authored an article on the birds of the Pongos Basin in the Peruvian Andes, published in the Wilson Journal of Ornithology. (You can read blog posts by Dan here.)  Several HMNS specimens were cited in the article, which is very cool.  (Plus, I learned what a pongo is.  Look it up for yourself and impress your friends and neighbors.)

The anthropology section in collections storage has been organized and practically transformed by Beth.  She has ensured that all those wondrous artifacts are properly labeled, stored, and easily located.  You have no idea how much work this entailed!  Imagine having all of your stuff from attic to basement labeled and neatly put away – with a color-coded key map.  Truly, my cold registrar’s heart is warmed and I get a little misty-eyed just thinking about it.

Anytime you get an in-house phone call that begins with, “I hate to bother you but” you know that intro is going to end with “do you know where David Temple is?”.  And I do know for certain that he’s been up in Seymour working on the museum’s ongoing dino dig with Dr. Bakker (read his posts here).  I doubled-checked with his wife Nicole.

When I climb upstairs to run some mail through the meter I notice it’s pretty calm in the Admin offices.  I think they’ve all finally rested up from last week’s very successful fundraising gala.  Poking my head into Kat’s office for a quick chat I found out that the education department is immersed in HMNS overnights, teachers’ workshops, and getting prepared for a full summer of a multitude of classes.  Don’t forget to register your kids pronto, those classes fill up fast.

Next, I quickly check on lunch plans with Tammy, manager of the museum’s mineral and fossil shop, who’s busy with all sorts of new specimens and arranging them in the cases.  She also provided her expertise at the gala’s mineral and fossil auction.  Passing by the museum’s visitor services desk I stop briefly to see if I have any mail.  It’s been a really busy day, probably due to the start of spring break, and Martha’s expression says it all.

There are some odds-and-ends photographs I need to drop off to the Volunteer Office, an always-upbeat place.  They’re happy to have found good homes for all the beardies but were so bereft without them, they bought one at the gala.  He’s been aptly named Ka-ching.

Lynn tells me the volunteers are eagerly studying up on the coming exhibits of The Nature of Diamonds and Terra Cotta Warriors: Guardians of China’s First Emperor. Karen’s in the midst of interviewing Ecoteen applicants and Araceli’s booking birthday parties.  Sybil was surrounded by volunteers so I’ll catch up with her later.

I actually don’t need anything from the exhibits guys, I’m just curious to see what they’re working on.  Today they are preparing one of our exhibit halls for the upcoming Terra Cotta Warriors exhibit. Mike and Glen are repairing some walls and ceiling tiles.  Soon they’ll be full bore into construction and layout.  Preston and Lex pour over exhibit floor plans.

The last colleague I touch base with is Christine, our live animal program manager.  She’s been out to a school with our Wildlife on Wheels program, sounds like the first-graders were adorable.  Next she demonstrates the Blue-footed Booby bird dance.  We both crack up.   I head back to the relative quiet of Collections knowing that even though I only spoke to a small portion of the staff, and not at any great length, this museum, along with its artifacts and specimens, is in excellent hands.

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Are You Making a Connection?

So, why are you here? What part of yourself did you bring today? What experience do you want to have? These are the questions I wish I could ask every one of you as you come through the museum’s doors. Then according to your answers I’d play matchmaker, pointing out an exhibit hall, hooking you up with just the right specimen or artifact so you could make a connection.

In today’s increasingly digitized world we are overwhelmed with visual images, most of which we ignore. You come to the museum and we’ve got…uh…more stuff for you to look at. Yet, you’re here. You could have stayed home twitching through a hundred television channels or trawling online for something, anything, about science. But you dealt with traffic and parking to experience something real, so what will you connect with and why?

Everyone coming to the museum brings their own individual history, likes and dislikes and those things obviously factor into the objects they find appealing. Suppose you love all things purple and you really like minerals, it’s no big revelation that one of your favorite specimens at HMNS might be the amethyst geode in the mineral hall. At this point, mentally Rolodex the specimens and artifacts you’ve come to love at HMNS. What do you never tire looking at, what do you always re-visit? Fossils? Shells? Taxidermied wildlife? A Native American pot? You can probably easily state the reasons why, too. Old stuff’s cool, shells are pretty, animals fascinate me, etc., etc. But let’s dig a little deeper.

Model: giraffe
Creative Commons License photo credit: jrsnchzhrs

Think of an object at the museum that caught your attention for no particular reason, it sorta surprised you. It might have been nothing special until you read the label, learned something new, and suddenly you saw that object differently. Or across the gallery something grabbed your eye and you absolutely had to know what that thing was. Aha! A connection’s been made, you’re not completely sure why, but you enjoy it and now it’s a favorite thing to see and share with others when you visit the museum.

Let me assure you, that very real connection between you and your special item can’t be downloaded or digitized. To illustrate I’ll share one of my favorites - but I have to cheat a little. This specimen’s not on exhibit but is part of the vertebrate zoology collection. A few years back a giraffe died of old age at the Houston Zoo and the skull was sent over to Dr. Brooks, our Curator of Vertebrate Zoology. The giraffe was Hi-Lo, whom I remember fondly from my childhood zoo visits (that’s my personal history connection) so I was pleased his skull came into our collections. Then I observed that the horns, those knobby things on a giraffe’s head, are actually bone. Somehow I thought they’d be some sort of spongy cartilage. Who knew? But I gained new insight. Last, for no reason I can defend, I truly love the slender elongated sculptural beauty of the skull. It’s just cool. Yeah, I can google an image of a giraffe’s skull on any computer but it’ll never delight me the way that Hi-Lo’s does.

Ok, a connection’s been made. Where will it take you? Does it inspire enough to pursue further knowledge or is the experience of the connection enough in itself? As a child, the late great Stephen Jay Gould so loved the dinosaur skeletons at the American Museum of Natural History that he became a renowned paleontologist. Me? I enjoy looking at the giraffe’s skull over and over again but am content to remain a registrar. And here’s some more musings regarding our connections with objects. Why do we take photos of our favorite things in museums? Why do we take photos of ourselves with them? Why do we buy replicas of them in the museum gift shop?

Pharaoh hats
Creative Commons License photo credit: Zepfanman.com

Whew, lots of questions in this blog! Now it’s your turn, let’s make this a discussion. Which objects do you think best represent the museum; are there iconic objects that connect with every visitor? Communicate with us; tell us what your favorite HMNS artifacts and specimens are and why. Because, if I could, the last question I’d ask when you go out the museum’s doors would be: Did you make a connection?

Donna Meadows
Associate Registrar, Acquisitions

Ike-ster…what a mess of things you made!

bye bye ike.
Creative Commons License photo credit: tiny white lights

Thus far, my previous blogs have been exploiting some of my old camp journals that are just collecting dust at home.  I’m going to be a bit radical this week and write about a recent topic rather than an event that occurred a decade or two ago.  Today’s blog involves some brief anecdotes I jotted down regarding the recent Hurricane that struck our beloved Houston early in the morning (dark) on 13 September 2008. 

When friends and relatives asked me how it went post-hurricane, without power and many of the creature comforts our society has grown so used to, I replied, “it feels balmy and tranquil, much like my old study site in Amazonia” (which, incidentally, will be the focus of next month’s entry).  A long-time friend of mine named John described the events at his house as ‘Hurrication,’ where the teens were forced to interact with the rest of the family through playing board games, consuming massive quantities of perishable food during marathon cookouts, and everyone generally having a great time despite circumstances.  With no power, roads blocked by downed trees and electrical lines, and lines to purchase gasoline not worth the struggle, it was a great time to deflate and smell what remained of the flowers.  My family and I went on many walks to cool off since the outside was overall cooler than the inside the house.  During this time we made various observations of how the storm affected the local urban wildlife, which I will attempt to recount below.

- Vegetation was mangled, or completely removed in many cases.  Huge pine trees with a diameter exceeding a yard were snapped clean off at the base like a toothpick.  The animals which depended on such plant communities to thrive had their lives thrown into complete chaos, through their habitat being mangled, or completely removed. 

Blue Jay 13
Creative Commons License photo credit:
BobMacInnes

- It had been a couple of years since we had seen any Blue Jays (Cyanocitta cristata) in our yard, yet several individuals passed through after the storm, trying to stake out a new territory.  One pair even chased a large Buteo hawk into a tree in our front yard, where it rested briefly before being found and further harassed by the jays.

- We figured mosquitoes would be abundant from the rain that followed the storm, but not a one.  Most wildlife was noticeably lacking.  I was extremely disturbed at absolutely no sign of any of the four species of doves commonly found in the neighborhood, and you can guess my relief when they began to return six days after the storm.  It is very likely that many of the birds left the region well in advance of the storm.  Wildlife seems to have an internal barometric gauge.  For example, prior to the massive typhoon in south-east Asia, much of the wildlife left the coastal forest for the higher interior forest.

Click
Creative Commons License photo credit: mandj98

- Whereas some wildlife left prior to the storm, other species stayed and were noticeably more active.  An unusually high number of Carpenter Bees (Xylocopa sp.) were all over our house gardens, perhaps trying to find new resources since their former founts were now gone.  Similarly, displaced Fox Squirrels (Sciurus niger) were actively scurrying about in search of a new dwelling in light of the huge piles of fallen trees and limbs.

- A Red-eared Slider (Trachemys scripta) was found dead on the road on the corner of Haddon and Morse.  These aquatic turtles are not native to this region, but introduced through the pet trade.  The fact that it was at least a mile or two from Buffalo Bayou was amazing.  All the rain and mild flooding that followed the tail end of the storm may have transported this turtle from the bayou to the suburbs, where it sadly met its death.  We knew it was a young turtle, as the carapace (upper shell) was only 12.5 cm (5 inches) in diameter.

- Another casualty from the storm involved a flock of approximately 20 House Sparrows (Passer domesticus).  These were all over the sidewalk of a small alley by a Marble Slab ice cream shop in a strip shopping center near our house.  Perhaps they had taken cover in the only thing they were able to find once the storm got really rough, where they sadly met their death.  Like the turtle mentioned above, these non-migratory (i.e., annual resident) birds were also introduced to the U.S.

Without a doubt, for me personally, the most unfortunate aspect of Ike’s wrath was the devastation it did to various reserves that are crucial to migrating Neotropical songbirds.  High Island, Bolivar Peninsula, Sabine Woods and Anahuac National Wildlife Refuge are only a few of these sites that were hit really hard.  However, with time and effort by loyal volunteers, these refuges will again be hotspots for Neotropical avian migrants passing through our beloved state of Texas.

-D.B., 13 October 2008
(1 month after Ike hit)