Egyptian Plover

Egyptian Plover at the Milwaukee County Zoo

The Egyptian Plovers have long been one of my favorite birds at the Milwaukee Zoo, but before I got my new camera I could never get good shots of the enclosure. Well my photo drought has ended!

I'm drawn to this little bird by its small size and striking, contrasting colors. What a looker! This, and their nesting habit (which we will get to later) make them a very distinctive shorebird.

Egyptian Plovers can be found living near sandy riverbeds throughout Sub-Saharan Africa. They are sometimes called "Crocodiles Birds" due to a 5th century BCE account by Herodotus stating that they pick food from between a Crocodiles teeth. The story has persisted, but there is no actual proof that the birds engage in this risky feeding behavior.

In reality, Egyptian Plovers feed on insects, seeds, and the occasional mollusk. They tend to remain sedentary, and breeding pairs will aggressively defend their territory. These couples will produce 2-3 eggs at a time which they bury them in the sand! Burying the eggs helps to keep them warm, and also helps to protect them from the eyes of hungry predators. But sometimes the eggs get too hot, so in order to cool them down the parents will wet their feathers and use the water to chill the eggs. Baby Plovers leave their "nests" when they are only a day old, though they will stick around their parents for about a month.

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IUCN Status : Least Concern
Location : Sub-Saharan Africa
Size : Length up to 8in (20cm)

Classification : Phylum : Chordata -- Class : Aves -- Order : Charadriiformes
Family : Pluvianidae -- Genus : Pluvianus -- Species : P. aegyptius

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Morelet's Crocodile

Crocodylus moreletii

Allow me to introduce you to the Morelet's Crocodile, named for P.M.A. Morelet who discovered the species in 1850. This species, which lives in Central America, grows to lengths of up to 3m. They can be found in secluded freshwater swamps and marshes near the Gulf of Mexico.

Morelet's Crocodiles have been in trouble for a number of decades. They have been illegally hunted since the early 20th century because their skin can be used to make high quality leather. Habitat destruction has also hurt the species. Since the 1970s they have been monitored by the Crocodile Specialist Group, and their numbers have been improving.

Behavior wise, Morelet's Crocodiles are considered to be shy, which is why they prefer secluded habitats. They have the distinction of being the only New World Crocodile that they exclusively build mound nests for their eggs. These nests can be 3m wide and 1m tall, and the female will guard over their eggs until they hatch. She will then dig out her offspring and carry them to the water.

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IUCN Status : Least Concern - Conservation Dependant
Location : Guatemala, Belize, Mexico
Size : Length up to 9.8ft (3m)

Classification : Phylum : Chordata -- Class : Reptilia -- Order : Crocodilia
Family : Crocodylidae -- Genus : Crocodylus -- Species : C. moreletii

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Elegant Tern

Thalasseus elegans

Today's animal is a migratory bird with a long bill and a nifty black crest. Elegant Terns live off the Pacific North American coasts, hanging out at different latitudes during different points of the year. They are shore birds and are very rarely found inland.

Elegant Terns have a massive migration route, though it as not as long as that of their Arctic Tern cousins. They spend their summers breeding up near California and Mexico, and then winter as far south as Chile. Interestingly, it is estimated that 90%-97% of all Elegant Terns nest in one colony on Isla Rasa in the Gulf of California, Mexico!

Elegant Terns breed in monogamous pairs, and both parents help to incubate and feed the chicks. Chicks leave the nest after only a week, and they join a large colony, or creche, of similarly aged young birds. They will stay with the creche for a little over a month, and their parents will continue to feed them during that time. Once they fledge, they remain near their family for several more months.

Elegant Terns are carnivores that feed primarily on fish. They hunt by flying over the water, adn then diving down swiftly to snatch up a meal.

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IUCN Status : Near Threatened
Location : Pacific Coasts
Size : Body length 16in (41cm), Wingspan 42in (107cm)

Classification : Phylum : Chordata -- Class : Aves -- Order : Charadriiformes
Family : Sternidae -- Genus : Thalasseus -- Species : T. elegans

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Pygmy Mammoth

When one thinks about Mammoths, they probably conjure up images of absolutely gigantic, hairy elephant-like mammals. The Pygmy Mammoths of the Channel Islands skew that image a bit- many were less than half the size of their mainland relatives!

At some point tens of thousands of years ago, a group of Columbian Mammoths made a six mile swim out to Santarosae, a "superisland" that existed when the ocean was 300 feet lower. Today only the very highest land points remain above water, and form four of California's Channel Islands.

Pygmy Mammoth Model from the Field Museum

Why did these 14ft tall, 20,000lb Mammoths swim so far? Perhaps they were allured by the smell of food! Mammoths, and modern Elephants, are excellent distance swimmers thanks to their trunks and buoyant bodies, so travelling a few miles for a buffet of fresh vegetation is a definite possibility!

Once on the island the Mammoths bred and the population grew. At the same time, the water levels rose, creating a larger gap between the island and mainland and trapping the Mammoths. As the number of animals rose, the amount of food fell. Having a smaller size (and thus requiring less sustenance)  became the favored trait, and the Columbian Mammoths evolved and diverged into a new species.

Pygmy Mammoths were comparable in size to our modern Clydesdale Horses. They rarely stood larger than 7ft and weighed around 2,000lbs. A very far cry from the species they evolved from!

Fossils have been discovered on four of the Channel Islands, with the first specimens uncovered in the 1870s. A near-complete skeleton was unearthed in 1994.

Radiocarbon dating has shown that Mammoths were living on the islands for over 40,000 years. However, the species went extinct around 11,000 years ago, which was around the same time that many of the mainland megafauna species were also dying out.

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Status : Extinct for 11,000 years
Location : Channel Islands, California
Size : Height up to 7ft (2.1m), Weight up to 2,000lbs (910kg)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Proboscidea
Family : Elephantidae -- Genus : Mammuthus -- Species : M. exilis

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Morganucodon

Morganucodon

Meet some of the very first mammal-like creatures, members of the genus Morganucodon. Fossils of these tiny rodent-resembling animals have been found across Europe, Asia, and North America.

Morganucodon is named for Glamorgan, Wales, where it was first discovered in 1941. The remains date back over 200 million years, to the late Triassic period! For some perspective, that is over 100 million years before T-Rex even showed up!

Members of the genus are so interesting because they have both mammalian and reptilian characteristics, though they are classified as mammals. They have hair and teeth like mammals, but their lower jaw is reptilian. They also laid eggs and had venomous spurred feet like modern Platypuses do! Morganucodon ate insects and was most likely nocturnal, based on the eye size.

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Status : Extinct for 200 million years
Location : Europe, Asia, North America
Size : Body Length around 4in (10cm)

Classification : Phylum : Chordata -- Class : Mammalia -- Order : Morganucodonta
Family : Morganucodontidae -- Genus : Morganucodon

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Dusky Dolphin

Lagenorhynchus obscurus

The Dusky Dolphin is a small little Cetacean that rarely grows longer than 2m. They can be found in coastal waters throughout the Southern Hemisphere, and are divided into three subspecies based on location. These groups live near New Zealand, in the Indian Ocean, and off of South America.

The species is known for its acrobatic skill and they are frequently seen leaping and jumping in groups. They are also very fond of boats, and like to swim and tumble alongside them. Dusky Dolphins are fast swimmers, and can reach speeds of up to 20 knots.

Dusky Dolphins live in interesting social groups. At night when they swim closer to shore their group is very small, numbering somewhere between 6 and 15 individuals. But during they day they swim to deeper water and join up with other groups in order to cooperatively hunt, play, and socialize. These gatherings can include several hundred dolphins. At night they break up again into their smaller sections.

The small social groups themselves seem to be strong, but there are no strong bonds between mated pairs. Dusky Dolphins are promiscuous breeders, and males compete with each other over females.

There are no good population estimates for the Dusky Dolphins. As a result, we don't know for sure how much hunting for food and bait, and gill-net tangling has affected their numbers.

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IUCN Status : Data Deficient
Location : Coastal waters in the Southern Hemisphere
Size : Length around 6ft (1.8m)

Classification : Phylum : Chordata --Class : Mammalia -- Order : Cetacea
Suborder : Odontoceti -- Family : Delphinidae -- Genus : Lagenorhynchus -- Species : L. obscurus

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Carolina Wren

The Carolina Wren is a stout little cinnamon colored bird that lives in the eastern parts of North America. They are year-round dwellers, but are sensitive to the cold. Because of this, their more northern populations tend to shrink after cold winters, though in recent decades the warmer winters have caused the species to spread north.

Thryothorus ludovicianus

Carolina Wrens are unique among Wrens in that only the male is a loud singer. They actually have one of the loudest songs, by size, of any bird, and it is often described as sounding like teakettle-teakettle-teakettle. One captive male Wren was such a prolific singer that he was recorded doing 3,000 songs in a single day!

Pairs will form at just about any time of the year, and they will remain monogamous, often for several years. The male and female will stake out a territory that they will nest and forage for food in. They will build nests just about anywhere, including in trees, in mailboxes, on stumps, and even in old boots! A pair will raise multiple broods in a single year, with the female incubating and the male bringing food.

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IUCN Status : Least Concern
Location : Eastern North America
Size : Length around 7in (18cm)

Classification : Phylum : Chordata -- Class : Aves -- Order : Passeriformes
Family : Troglodytidae -- Genus : Thryothorus -- Species : T. ludovicianus

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