Mean green flying machines: the hummingbirds are here!

Photo by JC Donaho. http://jcdonaho.com/

Photo by JC Donaho. http://jcdonaho.com/

What was that high pitched chirping and flash of iridescent green that just whizzed past at lightning speed? You just got buzzed by a hummingbird! The fall migration is passing through Houston, and these feisty little birds seem to be particularly abundant this year. Houston does not have (for the most part) any resident hummingbirds, but a few species pass through in spring and fall as they fly between their nesting grounds in the northern states and Canada, and their wintering ground in Central America.

The northward spring migration is much more diffuse than the fall event – you may hear a hummingbird or two in February or March, but they don’t linger. However, in late August through September and into early October, hummingbirds can be very evident in Houston. These marathon travellers will pass through our area for about 4 to 6 weeks, stocking up on fuel to take them over the Gulf of Mexico to their winter abode. They are particularly abundant on the Gulf Coast, where inclement weather can force them to stay put until a more opportune time comes to complete the migration. Rockport, Texas hosts a huge “Hummerbird Festival” every mid-September, with lots of talks on hummingbirds and other birds, butterflies, etc., and home tours to see gardens that are particularly full of hummingbirds. It’s over for this year, but put it on your calendar for future years and check it out!

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Most hummers you see in Houston (and in Rockport) are Ruby-throated Hummingbirds. Males are a metallic green with white bellies, and are named for the patch of dark feathers on their throat that glows a brilliant, iridescent ruby red when the sun hits it just right. Females and immature males do not have the spectacular throat coloring, and are white underneath. Some young males may have a fleck or two of red on their throat.

Two other species are sometimes seen here – the Rufous Hummingbird and the Black-chinned Hummingbird. Juveniles and females of these species are a little hard to distinguish from Ruby-throated females and youngsters, but the males are distinctive. Rufous males are a bright bronze color, with an orangey red throat. Black-chinned males are green with a black throat, below which, in the right light, a brilliant violet band will flash.

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Farther west, in the Big Bend area and west into New Mexico, Arizona, and California, hummingbird diversity is much higher. About 15 or so species are known from the USA, and most of these occur in the western states. For the apex of hummingbird diversity, head to the highlands of South America (e.g., Colombia, with about 140 species), where dozens of different species can be seen, some of them truly spectacular. Most of these are residents in the tropics and do not migrate.

 

Male and Female Ruby-Throated Hummingbirds, slow motion, August 2010 from Hummer Lover on Vimeo.

All hummingbirds behave similarly. Masters of speedy, controlled flight, they can hover in place, move backwards and forwards, dive and soar with incredible speed and precision. They can reach speeds of up to 60 mph, their wings whirring at 80 beats per second. Males in particular are territorial and aggressive, cheeping furiously as they drive off rivals from a good food source.

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Hummingbirds’ main food is flower nectar, so they are important pollinators of certain species of plants. They especially seem to gravitate to red flowers, although other colors are visited. Their long thin beaks and even longer tongues allow them to reach inside floral tubes that are much too deep for most butterflies and bees. Since birds in general have a poorly developed sense of smell, flowers pollinated by hummingbirds typically have no scent.

Hummingbirds also eat small insects such as fruit flies and gnats, catching them on the wing or finding them inside the flowers they probe for nectar.

Bottle feeder with ant-guard

Bottle feeder with ant-guard

Because they love sweet fluids, it is easy to provide feeders for hummingbirds, and several designs are available. Hummingbird food is simple to make; you just need sugar and clean water. DO NOT use any other sweetener – including honey or other types of sugar –just your standard white table sugar. Use four parts water to one part sugar. Bring the water to a rolling boil, add in sugar and stir until it dissolves, then turn off the heat. Do not cook it too long or it will start to caramelize. Let the solution cool and you are ready to fill your feeders. Keep extra sugar solution in the refrigerator.

IMPORTANT! If you want to feed hummingbirds you must commit to regularly changing their sugar water food! Sugar water ferments and/or grows mold quickly, and when spoiled it can make hummingbirds sick. Since you will need to clean the feeders about every three days, do not fill them too full or you will waste a lot of sugar solution. Fill them from between ¼ to ½ full, at least until you see how fast the hummers empty them.

DO NOT add red food coloring, and avoid commercial solutions with food coloring. Coloring is not necessary, as most feeders have red parts built in to attract the hummers’ attention. Like spoiled sugar water, food coloring is bad for the hummingbirds’ health.

Every three days, even if your feeders are not empty, clean them thoroughly with hot water and refill them with fresh solution. At the end of the season you should sterilize the feeders either in the dishwasher or using a dilute bleach solution before drying and storing them until next year. I prefer to use glass feeders as these are easier to sterilize.

 

Perky Pet feeder

Perky Pet feeder

A few guidelines on feeder placement – hummingbirds are not at all shy, so you can put feeders near your house where you can enjoy watching their activity. I put one right outside my kitchen window, and hang others around my back yard, especially near trees or bushes where hummingbirds can perch between bouts at the feeder. If you put out more than one feeder (I recommend this!), don’t put them too close, and ideally place them out of sight of each other to avoid their being monopolized by one dominant male.

Salvia leucantha, aka Mexican Sage

Salvia leucantha, aka Mexican Sage

In a good season, you will have dozens of hummingbirds – and the more feeders, the more hummingbirds! I usually put out from 3 to 9 feeders, depending on activity. Of course, hummingbirds also visit flowers for nectar. The classic hummingbird flower is red with a long floral tube, but many others also bring them in. Some good choices are salvias (many varieties), hummingbird bush, coral vine, trumpet creeper, and russelia.

Salvia guaranitica, or Purple Majesty Sage

Salvia guaranitica, or Purple Majesty Sage

Of course, if you have outdoor cats, you should not put out hummingbird feeders or any other kind of bird feeder!

Did you know?

  • Hummingbirds are only found in the Western Hemisphere.
  • Hummingbirds’ jewel-like, glittering colors do not come from pigments, but result from the refraction of light hitting special structures on their feathers.
  • The Bee Hummingbird from Cuba, less than 2.5 inches long, is the world’s smallest bird.
  • The largest hummingbird is the Giant Hummingbird, from Patagonia, Chile. It is about the size of a cardinal, but only weighs half as much (about .65 ounces, or about 1/20th of a pound).
  • The longest hummingbird is the Black-tailed Trainbearer from Colombia. The male’s total length is about 10 inches, including its 6.5 inch tail!
  • The Sword-billed Hummingbird from Ecuador has a 4 inch long beak, almost as long as its body!
  • Check out the PBS Nature special on hummingbirds, “Magic in the Air,” for some amazing footage of these incredible creatures!

We’d like to introduce you to the four new species of African house bats

Editor’s note: This blog post is a summation of “New Species of Scotophilus (Chiroptera: Vespertiliondae) from Sub-Saharan Africa,” written by HMNS Curator of Vertebrate Zoology Daniel M. Brooks and John W. Bickham, and published as a monograph in the Occasional Papers of the Museum at Texas Tech University.

Sub-Saharan Africa is a hotbed of biological diversity. A seemingly endless stream of new species has been discovered from different locales every year for centuries. The idea of this great biodiversity is widely accepted and, in fact, celebrated. But advances in genomic sequencing and morphology and an increased ability to obtain reliable specimens while recording their location shows that we’ve really just hit the tip of the iceberg. Many individual clades (or groups) of species should actually be distinguished further from each other as unique species themselves.

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Distribution of the four new species in Africa

The conservation question

Hold on a second here. Why is this important? What kind of difference could it make if there are 15 or 19 or 30 species of house bats in the world?

Glad you asked! Having an accurate taxonomy (naming and classification system) guides conservation efforts, while incomplete records impede these same efforts. Look at it this way: if you don’t know that a species exists, how can you protect it? In our modern era, we’re seeing rapid climate change and urbanization, which puts habitats under stresses to which species cannot quickly adapt. Therefore, having complete records allows us to make more meaningful conservation efforts because we have a better picture of what we’re trying to conserve. Having an accurate taxonomy also helps us to learn about biogeography, evolution, biodiversity and biology in general.

Now on to the bats!

As of 2005, there were 15 species of Scotophilus (house bats) documented. These were distributed between Indonesia, mainland Asia, Madagascar, Reunion Island and mainland Africa. However, these 15 species do not accurately reflect our current knowledge of Scotophilus biodiversity.

A 2009 study by Robert G. Trujillo sequenced cytochrome-b (part of an organism’s DNA) in Scotoplilus. Cytochrome-b is found in mitochondrial DNA, which is the genetic material in mitochondria (the “energy factory” of cells, if you will). These sequences are very useful in determining species differentiation.

With this information, Trujillo identified four distinct clades (branches on a species family tree). These include clades 8, 9, 11 and 12. Brooks and Bickham examined specimens from each of these lineages to see if there were enough physical differences between the organisms to further classify them as distinct species.

The clades and species of Scotophilus studied for the mitochondrial cytochrome-b gene by Trujillo et al. (2009). The new species described in this  paper are circled.

The clades and species of Scotophilus studied for the mitochondrial cytochrome-b gene by Trujillo et al. (2009). The new species described in this paper are circled.

Brooks and Bickham used skull and body measurements to compare specimens of each lineage with specimens representing the appropriate nominate — “textbook specimens” — of a given species).

Basically, they got very specific: measuring specimens from one predetermined area, and compared them to the nominate “textbook specimens” to see what physical differences there may or may not be.

When they compared the specimens, we saw that the genetic differences between the clades matched up with physical differences, which is why I’m proud to introduce to you four new species of African house bats (Scotophilus)!

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Study skin of Scotophilus andrewreborii holotype

 

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Study cranium and mandible of Scotophilus andrewreborii holotype

Scotophilus andrewreborii
Andrew Rebori’s House Bat

It is our honor to name this species for Andrew N. Rebori (1948–2011). Rebori unknowingly touched lives and inspired many individuals, including many museum professionals. He always maintained a keen interest in animals, especially bats, which exemplified his spirit and attitude toward life: “Take flight every new day!”

Type locality: Kenya: Rift Valley Province, Nakuru District, 12 km S, 4 km E Nakuru (0º24′S, 36º07′E).

Diagnosis: Scotophilus andrewreborii is distinguished from S. dinganii from Natal by a combination of external and craniodental features. S. andrewreborii averages slightly larger in body size for most characters. Additionally the dorsal pelage in S. andrewreborii is more reddish than the browner dorsal fur of S. dinganii, and the ventral pelage in S. andrewreborii is orange versus a much darker grey in S. dinganii.

Cranial measurements in S. andrewreborii are smaller, with non-overlapping measurements for braincase breadth for males, and shorter mean skull length (18.9 in S. andrewreborii vs. 19.6 mm for S. dinganii), narrower zygomatic, shorter braincase height, narrower interorbital width (4.4 vs. 4.8 mm), decreased breadth across upper molars, and decreased breadth across upper canines for females.

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Study skin of Scotophilus livingstonii holotype

 

Study cranium and mandible of Scotophilus livingstonii holotype.

Study cranium and mandible of Scotophilus livingstonii
holotype

Scotophilus livingstonii
Livingstone’s House Bat

It is our honor to name this species for the late David Livingstone (1813–1873). At a time when most of Africa was barely known compared to today, Livingstone, a young Scot of humble means, explored central Africa. Between 1841 and his death in 1873, Livingstone made several expeditions into the interior of the continent, mapping uncharted lands and searching for navigable waterways.

Type locality: Kenya: Western Province, Kakamega District, Ikuywa River Bridge, 6.5 km S, 19 km E Kakamega (0º13′N, 34º55′E).

Diagnosis: Scotophilus livingstonii is distinguished from S. dinganii from Natal by a combination of external and craniodental features. S. livingstonii averages larger overall in body size. Additionally the dorsal pelage in S. livingstonii is more reddish-mahogany than the browner dorsal fur of S. dinganii, and the ventral abdominal pelage in S. livingstonii is light buff vs. a much darker grey in S. dinganii.

Scotophilus livingstonii is also distinguished from S. dinganii from Natal by cranio-dental measurements. Male S. livingstonii have a shorter mean skull length, and females have a longer mean mandibular length.

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Study skin of Scotophilus ejetai holotype

 

Study cranium and mandible of Scotophilus ejetai holotype.

Study cranium and mandible of Scotophilus ejetai holotype

Scotophilus ejetai
Ejeta’s House Bat

This species is named in honor of Dr. Gebisa Ejeta, Distinguished Professor of Plant Breeding & Genetics and International Agriculture at Purdue University. He was born and raised in the village of Wollonkomi in west-central Ethiopia. Dr. Ejeta is a plant breeder and geneticist who received the 2009 World Food Prize for his research and development of improved sorghum hybrids resistant to drought and Striga weed. The results of his work have dramatically enhanced the food supply of hundreds of millions of people in sub-Saharan Africa.

Type locality: Ethiopia: Orimaya Region, Dogy River Bridge (8º21’43″N, 35º53’02″E). Collected at 1390 m above sea level.

Diagnosis: Scotophilus ejetai is distinguished from S. dinganii from Natal by a combination of external and craniodental features. S. ejetai averages smaller overall in body size, with females presenting non-overlapping forearm length.  Additionally the ventral pelage in S. ejetai has an orange hue, whereas the ventral fur is buff with a greyish abdomen in S. dinganii.

Cranial measurements in S. ejetai are smaller, with non-overlapping measurements for skull length, zygomatic breadth and braincase breadth for males, and zygomatic breadth and braincase breadth for females.

Study skin of Scotophilus trujilloi holotype.

Study skin of Scotophilus trujilloi holotype

 

Study cranium and mandible of Scotophilus trujilloi holotype.

Study cranium and mandible of Scotophilus trujilloi holotype

Scotophilus trujilloi
Trujillo’s House Bat

It is our honor to name this species for Dr. Robert Trujillo (b. 1975), whose ground-breaking doctoral dissertation on the molecular systematics of Scotophilus paved the way for the description of the four cryptic species described here. Dr. Trujillo’s dedication to science and environmental stewardship are reflected in his outstanding career in the US Forest Service.

Type locality: Kenya: Coastal Province, Kwale District, Moana Marine Station, 1 km S, 2 km E Ukunda (4º18′S, 39º35′E).

Diagnosis: Scotophilus trujilloi is distinguished from S. viridis from Mozambique Island by a combination of external and craniodental features. S. trujilloi averages larger in body size and shorter in forearm length, with females presenting non-overlapping head-body and forearm lengths. Additionally the dorsal pelage in S. trujilloi is mahogany, whereas the dorsal fur is brown in S. viridis. The ventral pelage in S. trujilloi is orange with a greyish abdomen, whereas the ventral fur is grayish-brown grizzled whitish abdominally in S. viridis.

Cranial measurements in S. trujilloi differ from S. viridis, with shorter mean braincase height in males; and females, as well as non-overlapping mandibular length in females. 

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.

Tales from Tanzania: Oh, the things you’ll find in a caldera

On the next leg of our trip, we visited the Ngorongoro Conservation Area.

NgorongoroNow, you may ask, “Nicole, your last adventure was in a national park, and this is a conservation area — what’s the difference?” And I’d answer that a conservation area has people living on it, whereas in a national park, no permanent settlements are allowed. The Maasi people live in the Ngorongoro Conservation Area with their cattle full time. They have been allowed this exception since they do not hunt. According to their traditional customs, they are only allowed to eat cow, goat and sheep so the wild animals in the crater have nothing to fear from them.

The Ngorongoro Conservation Area is especially interesting, as it contains the largest unbroken caldera in the world. It was created by a volcano, which has now collapsed. Before it collapsed, the volcano would have been much, much higher than Kilimanjaro.

The formation of a caldera

The crater has given rise to a variety of ecosystems due to its geography and sheer size. Moisture is pushed in from the ocean in the east, but it gets caught at the rim of the crater. The outside eastern edge of the crater, therefore, is home to a thick highland forest full of tropical birds. The west side of the crater only gets rain in the rainy season and most of the time looks something like dry west Texas.

Interestingly, the crater is responsible for most of what we have seen and what we will be seeing on this trip. The eastern edge of the crater is so dense that natural springs flow into Lake Manyara rather than the crater, keeping it green and providing a source of water for animals.

Looking to the west, when the volcano erupted 2.5 million years ago, the wind blew the volcanic ash to the Serengeti, which caused hard-packed earth that only the acacia can penetrate.

Later in the evening, we were able to talk to crater naturalist, Yotham, at our hotel. He was very surprised to see several of our pictures (we always knew we were looking at something awesome if one of the driver guides took out a cell phone to take a picture).

In particular, Yotham was surprised to see our shots of the Little Bee Eater, as they usually don’t come into the crater. Instead, they live in the highland forests on the outside western edge.

DSCN1517DSCN1205As we continued to go through our shots, he indicated that we had, in fact, had a very, very good day of observations.

Here are some of the highlights: 

Hyena kill: We arrived right after the wildebeest was taken down. Just out of screen are several other hyenas and 20 or so vultures waiting for their turn at the carcass. The eating hyena kept dragging the carcass away so it could eat without feeling crowded.

DSCN1604Ostrich: So, I learned something new today. When you see a male ostrich with a bright pink neck, it is feeling frisky. A male ostrich with a white or gray neck is not currently interested. Female ostriches are very beautiful but very differently colored than the male ostriches.

DSCN2036DSCN2048Serval: This picture is a bit miraculous. The serval is normally a nocturnal animal, so it was amazing to see it out during the day. AND THEN IT STARTED HUNTING. AND IT WAS AWESOME.

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