February birds at Van Cortlandt Park

A male Northern Cardinal splashes red and orange onto the browns of
dormant pants and the white of remaining snow.

Equal viewing for equal birds!

We are the united female birds of America,
and we demand to be seen!
(Black-throated Blue Warbler)

We are half of our respective species and
want your admiration too!
(Wood Duck)

Avi-feminism:
the radical notion that female birds
are equally beautiful
(Dickcissel)

The colorful lives of tanagers

Bay-headed Tanager (Tangara gyrola) near Maquipucuna Reserve, Ecuador

If you can see them, tanagers will make your eyes pop.

Chicken dinner...

Usually it's the chicken being eaten...

Chickens are the most abundant bird on Earth. Obviously this number would fluctuate any time dinner was being prepared, but in 2010, the United Nations Food and Agriculture Organization estimates there were 19.4 billion chickens on the planet. Thanks to the ease of production, the taste of fried chicken, and the flexibility of any-way-you-like-it eggs, there are more chickens than any other type of bird.

Run like an antelope

Thomson's gazelle (Gazella rufifrons) in Ngorongoro Conservation Area,

Tanzania. Look at all those flamingos in the background! What a life, to

run around free and enjoy the birds, without a care, except for lions,

cheetahs, leopards, and hyenas, of course.

The name antelope refers to a wide variety of mammals. Although antelopes are extremely diverse, they all share some basic characteristics.

White-bearded gnu (a subspecies of blue wildebeest (Connochaetes 

taurinus albojubatus) in Ngorongoro Conservation Area, Tanzania.

Antelopes are even-toed, hoofed mammals. They share this foot morphology with hippopotamuses, warthogs, giraffes, and deer, but none of those are "antelope."

Female eland (Taurotragus oryx) in Akagera National Park, Rwanda.

Antelope are classified in the family "Bovidae" along with cattle (buffalo) and sheep. Something that distinguishes the Bovids from other even-toed, hoofed mammals is that Bovids have horns.

Kongoni (hartebeest) (Alcelaphus buselaphus cokei) in Serengeti 

National Park, Tanzania.

Topi (Damaliscus lunatus) in Akagera National Park, Rwanda.

Antelope have horns, not antlers. Deer, for example, are not antelope. If you think about the common white-tailed deer, you may remember the male has antlers. His antlers branch; horns of Bovids do not branch. Additionally, antlers are shed each year and then regrown. Horns are permanent and do not shed.

Female waterbuck (Kobus ellipsiprymnus) in Akagera National Park, 

Rwanda.

Most antelope species also exhibit sexual dimorphism. Sizes, coloration patterns, and the presence of horns may differ between the males and females depending on the species. Adult males of all antelope always have horns, but some females have them too. Male and female elands, for example, both have horns but differ in their shade of brown and how much hair they have on their necks. Male impala have horns but females do not (males and females also differ in size but otherwise look the same).

Bush duiker (Sylvicapra grimmia) in Arusha National Park, Tanzania.

Kirk’s dikdik (Madoqua kirkii thomasi) in Tarangire National Park, 

Tanzania.

Antelope vary greatly in size. Eland males can weigh nearly 950 kilograms whereas Kirk's dikdik reaches just 7 kilograms. Some dikdik species are even smaller (2-3 kilograms).

Bohor reedbuck (Redunca redunca) in Serengeti National Park, Tanzania

Some antelope species live in large herds, such as wildebeest and impala, but others like duikers live alone or in small groups. In some species, like waterbuck and gazelles, in the breeding season, the males split apart from herds and defend a territory. 

Impala  (Aepyceros melampus) in Serengeti National Park, Tanzania

Uganda Kob (Kobus kob thomasi) in Murchison Falls National Park,
Uganda

All antelope are grazers. What they graze upon depends on their habitat. Antelope inhabit ecosystems from desert to grasslands to dense rainforests. They eat plants and serve as the link in the food chain between the sun and the predators.

Male bushbuck (Tragelaphus scriptus) in Akagera National Park, Rwanda

Big antelope are preyed upon by lions, cheetahs, leopards, and hyenas, but smaller antelope are eaten by a wide variety of predators. Life as an antelope is a life on the move, in search of food and avoiding being the food. Run antelope run!

Works consulted

• Gomez, W., T. Patterson, J. Swinton and J. Berini. 2011. "Bovidae" (On-line), Animal Diversity Web. Accessed October 31, 2011 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Bovidae.html.
• Kingdon, Jonathan. The Kingdon Pocket Guide to African Mammals. Princeton and Oxford: Princeton University Press, 2004.
• Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. "Horns and Antlers." 2006. The Animal Diversity Web (online). Accessed October 31, 2011 at http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/horns_and_antlers.html
• "Mammals: Antelope." 2011. Zoological Society of San Diego. Accessed October 30, 2011 at http://www.sandiegozoo.org/animalbytes/t-antelope.html

Beauty Pageant

Some birds just show it off. A group of seedeaters called Estrildids are small but especially attractive. Even the duller species have their flair. Let's take a look.

Male green-winged pytilia (Pytilia melba) at Agahozo-Shalom Youth
Village, Rwanda

Be sure to vote for your favorite estrildid in the comments section.

Female green-winged pytilia (Pytilia melba) at Agahozo-Shalom Youth
Village, Rwanda

Male red-cheeked cordon-bleu (Uraeginthus bengalus) at
Agahozo-Shalom Youth Village, Rwanda

Estrildids are little birds. All of the estrildids range from 9cm to 14 cm (3.5-5.5 inches) in length.

Female red-cheeked cordon-bleu (Uraeginthus bengalus) at
Agahozo-Shalom Youth Village, Rwanda

Male purple grenadier (Uraeginthus ianthinogaster) in northeastern
Tanzania. The female lacks the purple on the breast and belly, but
is as attractive with a purple-white eye mask and rich brown-white
striping on the belly.

Male red-billed firefinch (Lagonosticta senegala) at Agahozo-Shalom
Youth Village, Rwanda.

Female red-billed firefinch (Lagonosticta senegala) at Agahozo-Shalom
Youth Village, Rwanda. Note the red spot in between the eye and
the bill and the white spots on the belly. She's a cutie!!

Yellow-bellied waxbills (Estrilda quartinia) in vegetation on the shore
of Lake Kivu, Rwanda.

Black-crowned waxbill (Estrilda nonnula) in vegetation near the shore
of Lake Kivu, Rwanda

Common waxbill (Estrilda astrild) in swamp vegetation near Lake
Mugesera, Rwanda

Fawn-breasted waxbill (Estrilda paludicola) at Agahozo-Shalom
Youth Village, Rwanda.

Crimson-rumped waxbills (Estrilda rhodopyga) at Agahozo-Shalom
Youth Village, Rwanda

Grey-headed silverbill (Lonchura griseicapilla) at Tarangire
National Park, Tanzania.

African silverbill (Lonchura cantans) in northeastern Tanzania.

Bronze mannakin (Lonchura cucullata) at Agahozo-Shalom Youth
Village, Rwanda. 

I never managed to get a picture of the red-headed bluebill (only saw it six times between Rwanda, Tanzania, Uganda) or Peter's twinspot (seen once in Tanzania) but they would surely compete for the most spectacular estrildid in East Africa. Other esrtildids we saw include white-breasted nigrita, grey-headed nigrita, African firefinch, black-faced waxbill, black-headed waxbill, African quailfinch, cutthroat finch, black-and-white mannakin, and red-backed mannakin.

Shelley's Crimsonwing might have won it all, but I never got a glimpse of the bird. If you don't show up, you aren't in the pageant. Sorry, birdies, show up next time I look for you! We missed out on all the crimsonwings thus far, and we missed out on a few other neat twinspots and the white-collared oliveback. It's hard to see them all.

Please, comment below on your favorite estrildid. The winner gets a 2 centimeter tiara.

Boy, you're lookin' fine! Sexual dimorphism in birds

Ostriches (Struthio camelus) are sexually dimorphic. The male (right)
has a pinkish neck and legs, and black and white feathers. The female
(left) is mostly brown. 

When males and females of the same species have different physical forms, it is called sexual dimorphism. These differences can be in body parts, color patterns, and size.  If you are trying to identify a species, recognition that the sexes may appear different is key. I once met a woman who swore she had two species of cardinals in her yard, but after a bird walk she discovered the Northern Cardinal males are bright red whereas the females are greyish red. Same species, but different looking. 

Why?

Black-and-white casqued hornbills (Bycanistes subcylindricus).
The male on the left has a much larger casque on his bill and
less red bare skin around his eye than the female on the right. 

On the surface, it would appear that the bright colors, long tail feathers, different size, etc. are ways of attracting mates. But birds do not choose to look the way they do. These differences are produced by their genes. So why do the males and females of the same species look different?

I re-post this photo of southern red bishops (Euplectes orix) because
it shows the strong difference between the male (left) and the female
(right).

It would be easy to explain if females picked males with the sharpest claws, strongest wings, or some other characteristic that increased his chance of survival. This does happen in that only the individuals who can survive long enough to breed actually get to pass on their genes (natural selection). But color, tail length, and other “ornamentation” differences in birds are not so obvious. They have no apparent function other than attracting a mate.

A male pin-tailed whydah (Vidua macroura).

Males (and in a much smaller number of species, females) are driven to differences by the opposite sex that select them to breed with; then the genes of the male are passed on (sexual selection). So for example, if a male bird with a brighter red color than other males of its species, is chosen to breed by more females, then more of his genes are passed on to his offspring (assuming the brighter red color is a genetic).  With more genes for the brighter red color in the population, if females continue to select the brighter red males, then males continue to be the brighter red color. This is straightforward biology, but it still doesn’t answer the question of why the birds select differences in the first place.

Female pin-tailed whydahs (Vidua macroura).

We really do not know much about why birds select their mates when it comes to ornamentation. The fantastic details may help females distinguish their species from another similar one. The showy details may announce an individual’s presence so loudly that to defy getting eaten by a predator is to imply genetic superiority. It is possible that what we see as fantastic details are byproducts of some unforeseen trait; for a hypothetical example, it may be that the gene for long tails is just passed on because the birds who had them happened to have better territories or have stronger bones (but through no connection to the longer tail itself). 

A male black cuckoo-shrike (Campephaga flava) is dark and glossy with
just a small yellow gape behind the bill. 

Whatever the reasons may be, sexual dimorphism is a defining aspect in the appearance of many bird species. People sometimes ask me why the males are more beautiful, but I remind them that beauty is in the eye of the beholder. It is the female birds that do the choosing, so they have the power in the relationship (not to anthropomorphize). Inspired by slogans from the early 20^th century women’s rights movements (like “equal pay for equal work”), Michele and I joke about creating a feminist-birding blog dedicated to females birds called “Equal viewing for equal birds!” Although not as showy, female birds (and non-breeding plumage males and juvenile birds) have a subtle beauty that is worth seeing too. 

A female black cuckoo-shrike (Campephaga flava) is beautiful on her
own.

For more images of sexual dimorphism in birds, see the sunbirds and weavers.

Works Consulted

• Dawkins, R. The Greatest Show on Earth. London: Random House Group, 2009.
• Ehrlich, P, et al. "Sexual Selection." Birds of Stanford. Accessed: October 17, 2011. http://www.stanford.edu/group/stanfordbirds/text/essays/Sexual_Selection.html
• Fanshawe, J. and Stevenson, T. Birds of East Africa. Princeton and Oxford: Princeton University Press, 2002.
• Owens, I. and Hartley, I. 1998. "Sexual dimorphism in birds: why are there so many different forms of dimorphism?" National Center for Biotechnology Information. Accessed October 16 2011 at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1688905/pdf/RQQD3PMMWYMYQD4H_265_397.pdf

Chatting with Robins

White-browed Robin-chat (Cossypha heuglini). Vegetation by Lake Kivu,
Rwanda. This is also a common bird at Agahozo-Shalom Youth Village.
Muscicapidae (Old World Flycatchers)

One of the tricky aspects of bird lingo is that some common names do not carry over from location to location. In addition, some birds have names because of similar looking birds, but are not even classified in the same family. For example, one might assume that the American Robin (Turdus migratorius) and the European Robin (Erithacus rubecula) are closely related. Not so! They are actually classified in different families, with the American Robin in Turdidae (which contains Thrushes and other similar birds) and the European Robin in Muscicapidae (Old World Flycatchers). 

East Africa contains examples from both families, and they are delights!

Advice from little hornbills

Crowned Hornbill, Tockus alboterminatus, in trees near the shore 

of Lake Victoria, at Mabamba Swamp, Uganda

My first exposure to hornbills was likely Disney’s Lion King, where Zazu tries to keep Simba out of trouble. Much to my dismay, Zazu appears to be a fictionalized hornbill species. I can’t find a match*. The only “little hornbills” are the dwarf-hornbills of the Congo rainforest and Western Africa, and even they are not that small. Certainly, none of the hornbills have given me any advice, although I am no king lion.

Red-billed Hornbill, Tockus erythrorhynchus, West of Arusha, 

near Tarangire National Park, Tanzania. This is the species the Lion King

character Zazu is based, but see my discussion at the bottom of the page.

Hornbills are pretty special birds. They have long tails and are relatively large compared to most birds, ranging from 38 to 100 centimeters in length (about 15 to 40 inches). Hornbills have thick, down curved bills; some hornbills have large keratin casques that extend from the head over the bill. Hornbills are loud in their calls, hooting, rasping, and piping various sounds. Especially with the bigger species, they are noisy in flight too. In the West Usambara forests of Tanzania, I took pause to describe in my notes the sound of the Silvery-cheeked Hornbill in flight, a “huuh-huuh-huuh,” each “huuh” being a downward thrust of its wings. 

Von der Decken’s Hornbill, Tockus deckeni, West of Arusha, 

near Tarangire National Park, Tanzania

Hornbills are omnivores. They eat fruits, invertebrates, and small vertebrates like lizards. You will sometimes see a hornbill flick up its bill, tossing the food into the air, and catch its food further back in its mouth. 

African Pied Hornbill, Tockus fasciatus, Mabira Forest, Uganda

There are about 56 hornbill species in the world and that number may increase if certain subspecies are considered distinct. Different hornbill species live in different habitats, from savannas to rain forests. Twenty-four species (of the 56) can be found in Africa. The rest are in tropical Asia. We have a couple of birding friends who have lived in Asia and tell us that African hornbills have nothing on Asian hornbills. If that is the case, I have no idea, because all my hornbill sightings have been in Africa. 

African Grey Hornbill, Tockus nasutus, Akagera National Park, Rwanda

Michele and I have seen twelve species of hornbills, including the ground-hornbills. In some places, hornbills are quite common. In central-eastern Uganda, where native trees and even small patches of forest remain, hornbills could often be heard and fairly easily seen, especially the large Black-and-white-casqued Hornbill. In Rwanda, in my experience, I have only seen one hornbill out of a national park once, and that was by one of the only tiny native-wooded areas left. The Black-and-white-casqued Hornbill was present in Nyungwe Forest in Rwanda, but it was never easily seen (in fact a group of birders that we met there missed them altogether). I suspect that Rwanda’s lack of abundant hornbills outside protected areas has to do with the fact that nearly all its large native trees outside the parks are gone (hornbills breed in large trees). 

Black-and-white-casqued Hornbill, Bycanistes subcylindricus,
Entebbe Botanical Gardens, Uganda.  Note that the male on the left has
a larger casque and the female on the right has red bare skin around her eye.
This is a good example of sexual dimorphism, which means that males
and females of the same species differ in shape, plumage, or size.

With the sunbirds or weavers, the males are bright, and admittedly I photograph the males more than the females. But upon reviewing my shots of the hornbills, they were also all male. Female hornbills are very similar if not identical in plumage and their bills only differ in size of the casque and sometimes color. Why were there all males in the pictures? Michele suggested that maybe the males are showier; in fact, she was very close!

White-thighed Hornbill, Bycanistes cylindricus, Budongo Forest, Uganda.
The male and  female display very similar sex differences as the above
black-and-white-casqued hornbills. These two species are very similar
but can be told apart by amount of white on their primary feathers and the
differences in their tail feathers.

Hornbills have a unique reproductive strategy that makes the females less visible during parts of the year. The female hornbill seals herself in a tree cavity with the eggs, where she incubates them and rears the young. The male brings food to feed her and the young until the young birds are nearly ready to fly out. She even molts, losing her flying feathers, during her time inside the tree. All species of hornbills breed like this except the ground-hornbills.

Silvery-cheeked Hornbill (female), Bycanistes brevis, Amani Rainforest,
East Usambara Mountains, Tanzania

Silvery-cheeked Hornbill (male), Bycanistes brevis,
Lake Manyara National Park, Tanzania

The ground-hornbills are unique (endemic) to Africa. Ground-hornbills are also different from all other hornbills in several ways. The two species of ground-hornbills have different ranges, with one basically in Africa north of equator and the other in Africa south of the equator. Visually, they differ in two main ways. First, the casque on the bill of the Abyssianian species is larger and more pronounced than the Southern species. Second, the coloration of the exposed skin on the neck and face of each species is different. The Abyssinian has blue skin around the eye and on the neck with the male having a red neck with a blue patch. The Southern has red skin around the eye and on the neck with the female having a red neck with a dark blue patch. It sounds confusing, but these are huge birds without much overlap in range, so they are easy IDs.

Southern Ground-hornbill, Bucorvus leadbeateri, Lake Manyara
National Park, Tanzania. While this photo is poor, is hows the bird
in the process of flipping up food to catch further back in its mouth.

Abyssinian Ground-hornbill (male), Bucorvus abyssinicus,
Murchison Falls National Park, Uganda

Abyssinian Ground-hornbill (male), Bucorvus abyssinicus,
Murchison Falls National Park, Uganda. They fly too!

Abyssinian Ground-hornbill (female left, male right), Bucorvus abyssinicus,
Murchison Falls National Park, Uganda

The two hornbills that we saw but did not photograph are the Piping Hornbills and the Trumpeter Hornbills. If there is any advice to be taken from hornbills, it is that you need to take a lot of photos to get a good shot. And to keep big native trees so that birds can nest in them!!

* According to the Lion King Wiki, Zazu is a red-billed hornbill. This species would make sense in terms of distribution and habitat. The bill is red and it does have some yellow at the base. However, there are some serious differences between Zazu and red-billed hornbills. Differences are extremely important in birding, and the following differences are more than enough to say Zazu is not a red-billed hornbill.

Zazu’s tail has a white line going across the center of his tail feathers; red-billed hornbills have white trailing down the edges of their outer tail feathers with no white line going across. Legs and feet of Zazu are red, whereas red-billed hornbill legs and feet are black. Zazu has one white bar on his wings whereas red-billed hornbills have white splotches all over their wings. Zazu has no yellow bare skin around the eyes whereas red-billed hornbills do. Zazu is blue, light blue, and white. Red-billed hornbills are black and white.

These differences are major enough to rule him out as a red-billed hornbill (the argument of simplification in kids’ movies is possibly valid until you see that other illustrated birds in animated movies have the details near-exact). I am not trying to split hairs here with Zazu’s illustrators or imply that an animated bird should be true to form. I think it is cool to see species that are famous from movies or are exhibited in zoos; in this case, there is no Zazu species to see.

Works Consulted

• Fanshawe, J. and Stevenson, T. Birds of East Africa. Princeton and Oxford: Princeton University Press, 2002.
• Pearson, D.J., Turner, A.T. and Zimmerman, D.A. Birds of Kenya & Northern Tanzania. Christopher Helm: London, 1999.
• Roberson, Don. "HORNBILLS: Bucerotidae." Bird Families of the World. Accessed 21 September 2011. http://creagrus.home.montereybay.com/hornbills.html
• Roberson, Don. "GROUND-HORNBILLS: Bucorvidae." Bird Families of the World. Accessed 21 September 2011. http://creagrus.home.montereybay.com/ground_hornbills.html
• Ryan, P. and Sinclair, I. Birds of Africa south of the Sahara. Struik Nature: Cape Town, 2003