Meteorological spring starts Sunday, and we are already starting to hear the calls of early migratory birds, heading north from southern wintering grounds, working to establish territory their among the best nesting sites available.
Red-winged blackbird, Agelaius phoeniceus, singing by Rhododendrites, May 2023
Some birds, including red-winged blackbirds, Agelaius phoeniceus, get their cue to start spring migration as temperatures get warmer. These species head to prairies, forests, and wetlands to claim a location they can protect, call for a mate, and establish a nesting site with good protection and food sources. Other birds, including many warbler species, return in spring when daylight hours lengthen. Generally flying at night, they use star positions and the Earth’s magnet field to guide them. If nights are stormy or heavily overcast, early morning may find hundreds of them waiting in fields for clear skies. Birds may also stop for a day or two in areas located on the southern shores of any large body of water to rest and feed before crossing.
Red-winged blackbird, Agelaius phoeniceus, flock at sunset by Jerry Segraves
North America flyway map by USFWS
Bird species around the world generally follow established flyways, established routes over specific locations between their southern and northern territories. Many migration routes do not follow a straight path. Some species have historical stopover or feeding locations that provide a rest point along the way. Other species may not be able to cross a mountain range; or a large body of water can act as a barrier for land birds, but may be a required food source for wetland birds.
Arctic tern, Sterna paradisaea, adult & juvenile by Charles J Sharp, Aug 2025
Arctic tern, Sterna paradisaea, in flight by Charles J Sharp, Aug 2025
Long distance migration routes are most common for birds wintering in subtropical and tropical areas and breeding in the northern hemisphere. Long migrations in the southern hemisphere are far less common because there is less land near the South Pole to support breeding activities. The record holder for migration distance is the Arctic tern, Sterna paradisaea, overwintering in Antarctica and breeding in Arctic locations, a round trip between 30,000 and 55,000 miles. Some shorter migrations are between upper and lower altitudes in mountainous regions.
Penguin migration map by Fred Cooke & Jenni Bruce, Aug 2011
Dusky grouse male, Dendragapus obscurus, displaying by US NPS
Most birds migrate in flocks, which reduces the energy needed to fly long distances and provides added protection against predators. Penguins migrate without flying. Most penguin species swim between locations, covering up to 1,000 miles round trip. A few species cover long distances on foot, including dusky grouse, Dendragapus obscurus, in the Rocky Mountains which walk from lower to higher elevations. However, a flock may encounter unfavorable weather or flying conditions that causes a large number of birds to stall in one location, introducing other risks including depleted food sources and predation by land-based animals.
At the Jurica-Suchy Nature Museum, we host a nature walk every other week to observe changes in our campus including the birds that are moving through the area. There are many birding groups worldwide that provide opportunities to observe and learn about migratory birds in every location. Consider joining a group, or take your own bird walk as we have clear days and warming temperatures and see who’s on the move in your area.
It is getting to the end of summer, and many bird species that winter in Central and South America will soon be starting their migrations. Of the 320 species of hummingbirds, 15 spend the summer breeding in North America, from the Gulf Coast states to southern Canada, before returning to winter habitat farther south. Only one species, the Ruby-Throated Hummingbird, Archilochus colubris, breeds east of the Mississippi River.
7 of the 15 hummers that breed in North America:
Anna’s Hummingbird, Calypte anna, by Alan Scmierer-USFWS, Mar 2007
Black-chinned Hummingbird, Archilobus alexandri, by Paul Crook-USFWS, Jun 2024
Blue-throated Hummingbird, Lampornis clemenciae, by Alan Schmierer-USFWS, Jun 2024
Broad-billed Hummingbird, Cynanthus latirostris, by Alan Scmierer-USFWS, Mar 2022
Buff-bellied Hummingbird, Amazilia yucatanensis, by Alan Scmierer-USFWS, Jan 2010
Broad-Tailed Hummingbird, Selasphorus platycercus, by Tom Koerner-USFWS, Feb 2024
Allen’s Hummingbird, Selasphorus sasin, by Wendy Miller-USFWS, Jun 2024
Hummingbirds have a very high metabolism with a normal heart rate of 250 beats per minute that accelerates to almost 1250 beats per minute when in flight. They consume large amounts of nectar each day to get enough sugar to support their energy requirements. Several small grooves running the length of their tongue funnel nectar into their throat by capillary action, a force that causes liquid to rise in a small tube without needing to use air to suck the liquid in. They also eat any small invertebrate to fulfill protein, vitamin, and mineral needs. Hummingbirds snatch insects mid-air while in flight, poach them from spider webs, and glean tiny moth caterpillars from new leaves and branch tips. Another foraging method uses the blast of air beneath their powerful wings to roll over leaves on the forest floor, revealing the insect life below.
Anna’s hummingbird catching insects by Stan Lupo, Jul 2023
Hummingbirds do not bond with a mate. Females establish a territory that optimizes the available nectar and offers multiple nest sites. Males establish a territory based on encountering as many females as possible. Both will defend their areas from other hummingbirds, as well as other nectar feeders including butterflies and bees. Daily feeding starts on the outer edge of their territory to chase out any overnight interlopers and ends with nectar sources deep inside the area’s interior. Males will breed with as many females as possible. Females may have more than one brood of eggs each year, either concurrently or one brood following another.
Nests are about 2″ in diameter, built of small twigs, lined with soft plant material, and covered on the outside with greenish-gray lichens. Nests are bound to branches with spider silk, usually in a forest clearing. The lichens provide camouflage by making the nest appear as a large knot when seen from below. Females reach breeding age at the end of their first year, and can breed throughout their lifetimes. They construct one or more nests, each containing two white eggs, the size of peas, which are incubated by only the female for 14 to 16 days. The male takes no part in raising the young birds, coming together with the female only during mating.
Allen’s Hummingbird nest, by Mike’s Birds, Mar 2013
Ruby-throated hummingbird on nest with lichen, by Lorie Shaull, Jul 2020
Hummingbirds found in the western portions of North America travel overland migration routes. However, midwestern and eastern birds fly non-stop over the Gulf Of Mexico. A hummingbird can increase its fat reserves and double its body weight in the 7 to 10 days prior to the overseas trip. Through studies using banded birds, we have learned that they fly alone, normally at night, along with large flocks of other birds. Young birds, making the trip for the first time, can successfully navigate the migration route with no prior training. Their guidance system, how it works, and how it is learned are all still a mystery.
No hummingbird species are listed as endangered. However, hybridization among species is common, and their small size and great speed make them very difficult to count and track. Little data is available about population size changes and movements; however, more birds have been found over-wintering as far north as the Gulf Coast states of North America.
At the Jurica-Suchy Nature Museum, we have numerous bird specimens on display, including hummingbirds. We welcome you to come in and learn more about these amazing creatures.
Remaining 8 species that breed in North America:
Calliope Hummingbird, Selasphorus calliope, by Barbara Wheeler-USFWS, Nov 2021
Costa’s Hummingbird, Calypte costae, by Wendy Miller-USFWS, May 2020
Rivoli’s Hummingbird, Eugenes fulgens by Doug Greenberg-USFWS, Aug 2017
Lucifer Hummingbird, Calothorax lucifer, by Jim Gain-USFWS, Mar 2022
Ruby-throated Hummingbird, Archilobus colubris, by Alan Scmierer-USFWS, Jun 2024
Rufous Hummingbird, Selasphorus rufus, USFWS, Jun 2024
Violet-crowned Hummingbird, Amazilia violiceps, by budgora, Mar 2014
White-eared Hummingbird, Basilinna leucotis, by Alan Scmierer-USFWS, Mar 2022
Sea turtles live in every ocean environment around the world, nesting on tropical and subtropical beaches, and migrating long distances. They spend their entire lives at sea except when females come ashore to lay their eggs. They have been on earth for over 100 million years, surviving the period when most dinosaurs and other reptiles died out 65 million years ago.
Coral reef & hawksbill sea turtle by jakubgojda, Indian Ocean, Maldives
Sea turtles are large, air-breathing reptiles with upper (carapace) and lower (plastron) shells. Six of the seven species are covered by hard scales called scutes. Although none have teeth, jaws are suited to each species specific diet. Sea turtles do not have ears, but there are eardrum openings covered by a flap of skin. Their sense of smell is excellent as is their underwater vision, although they are nearsighted when out of the water. Along with a streamlined body, they possess powerful legs and claws for swimming, diving, and catching food.
Green turtle eating seagrass by LauraDin, Getty Images
Green sea turtles, Chelonia mydas, on coral reef by Artush, Alam, Egypt
Sea turtles, along with manatees, are excellent caretakers of seagrass beds and coral reefs, habitats that are vital to the reproduction of fish, shellfish, and crustaceans. Seagrass, one of their favorite foods, grows faster and stronger with daily trimming from turtle munching. Coral beds, vulnerable to collapse and suffocation under mass quantities of sponges and small crustaceans, benefit from sea turtles that eat several hundred of these animals each day.
Olive ridley digging egg chamber by JHVEPhoto, Getty Images, Costa Rica
Green sea turtle hatchlings by Penny Britt, Getty Images
After reaching sexual maturity, which takes from 15 to 50 years, depending on the species, female sea turtles return every two to five years to the beach where they were born to lay their eggs. On average, they dig three to seven nests and place about 100 eggs in each. Baby sea turtles break out of their egg and instinctively flee for the lighter colored horizon where the ocean meets the beach. They spend several years in the open ocean feeding and growing before venturing into shallower waters to eat, mate, and reproduce. Only about one in a thousand babies will grow to be an adult. Most are prey for birds, crabs and fish, but many are killed by humans for food, medicines, and religious ceremonies. Nesting site habitat destruction and turtles caught as part of the fishing industry also play a part in population decline.
Jellyfish & jacks by melissaf84, Getty Images, Coral Sea; Whelks by Pack-Shot, Getty Images; Reef crab by JohnAndersonPhoto, Getty Images, Lembeh Strait, Indonesia; Posidonia seagrass meadow by Arnaud Abadie, Getty Images Signature, Mediterranean Sea
Females lay all of their eggs on land, but nesting sites and the best feeding sites may be thousands of miles apart. Sea turtles are found throughout the world’s oceans following concentrations of jellyfish, sponges, and crustaceans found in coral reefs and seagrass beds. Leatherback females have been tracked making migrations of over 12,000 miles between nest sites and the best annual feeding grounds during non-breeding seasons.
Read facts on each species in the sidebar, shown below. Come to the Jurica-Suchy Nature Museum where we have loggerhead, hawksbill, and green sea turtles on display to learn more about these creatures and their hidden realms.
Pics 1&2: Green sea turtle, Chelonia mydas, by DonArnold, JSNM 2023; Pics 3-6: Hawksbill sea turtle, Eretmochelys imbricata, by DonArnold, JSNM 2023; Pic 7: Loggerhead sea turtle, Caretta caretta, by DonArnold, JSNM 2023
Sea turtle species…
There are seven species of sea turtles in the world. All are experiencing dwindling populations from various threats. Two are critically endangered: the hawksbill sea turtle and the Kemp’s ridley sea turtle. Two are endangered: the green sea turtle and the flatback sea turtle. Three are listed as threatened: the leatherback sea turtle, the olive ridley sea turtle, and the loggerhead sea turtle.
Hawksbill sea turtles, Eretmochelys imbricata, have a narrow head allowing access to tight spaces in coral reefs, the usual spot to find sponges. They consume 1,000 pounds of sponges annually, keeping coral reefs free from suffocation by the sponges. These turtles are medium size at 2′-3′ and 100-200 pounds. Females nest on beaches among rocky areas 3-4 times in a season and lay 140-200 eggs in each nest.
Hawksbill portrait, Eretmochelys imbricata, by Sheraca, Dec 2014; Hawksbill sea turtle, Eretmochelys imbricata, by Goug Finney, Sep 2019
Kemp’s ridley sea turtles, Lepidochelys kempii, are the smallest species at 2′ in diameter and 75-100 pounds. Kemp’s ridley turtles have made a huge recovery from the 1960s, when there were about 200 individuals left, to almost 9,000 today. This is due to changes in Mexico’s laws, where 95% of their nesting takes place, to protect nest sites from disturbance.
Kemp’s ridley sea turtle, Lepidochelys kempii, by USFWS, Sep 2010
Green sea turtles, Chelonia mydas, grow to 4′ and 500 pounds. They are herbivores with a finely serrated beak for biting seagrass and scraping algae from hard surfaces. This is the only species known to come onshore to bask in the sun. They are named for the color of their fat, not their shell.
Green sea turtle, Chelonia mydas, by Florida Fish&Wildlife
Flatback sea turtles, Natator depressus, have a flattened carapace, unlike other turtles. They are medium sized at 3′ and 200 pounds. Found only in Australia, they do not migrate. Females lay only about 50 eggs in a nest, but nests are well spread out, helping to better protect their eggs. Their biggest threat is being preyed upon by saltwater crocodiles.
Leatherback sea turtles, Dermochelys coriacea, are the largest species at 4′-8′ and 500-2,000 pounds. They consume mostly jellyfish, daily eating their own weight in food. They have no scutes, but are covered by a flexible, leathery skin that allows them to dive up to 4,000 feet deep searching for prey. These turtles have thermoregulatory adaptations that allow them to hunt in very cold waters from Alaska to Chile, and they regularly make the longest migration of any vertebrate animal, traveling over 12,000 miles annually.
Leatherback sea turtle, Dermochelys coriacea, by Claudia Lombard, USFWS, Jun 2011
Olive ridley sea turtles, Lepidochelys olivacea, are small at 2′ and 75-100 pounds. They are the most abundant of all species. On certain beach sites, nesting females form an arribada, a grouping of all the females offshore who all come ashore at the same time to nest and lay eggs. Females on other sites may nest alone. Arribadas are particularly vulnerable to mass mortality events, but these are rare and population numbers remain consistent.
Olive ridley sea turtle, Lepidochelys olivacea, by Charles Peterson, Head Start Programs, Oct 2002
Loggerhead sea turtles, Caretta caretta, grow to 4′ and 200-400 pounds. Their very large heads and jaws can easily crush hard shells, allowing them to eat crabs, conches, and whelks. They have the largest concentration of nests annually, including 30,000 at a single Mediterranean location. Their shells provide space for 50 to 100 epibionts: plants and invertebrates that live permanently attached to their shells.
Loggerhead sea turtle, Caretta caretta, & epibionts by actor212, Aug 2017
Elephants are the largest land mammals and they live in a variety of habitats in tropical and subtropical regions. Their native habitat is often savanna, grassland or forest although they can also be found in desert, swamp, and highlands. These areas get twelve hours of sunlight each day, with warm, daily temperatures averaging from the lower 70s to above 100˚F for animals living in the desert. Heat and gravity are two natural factors that affect all large animals, and elephants have some unique methods and body design to compensate for both.
Walking in Kruger National Park by Simone Eman, simoneemanphotos
Elephants have a massive skeleton with solid bones in their feet, legs, hips, and ribs that provide excellent support for all of their weight. Lots of muscles, both large and small, allow easy movement while still protecting their vital organs. But not all of the bones are solid. The skull is honeycombed throughout, so it is light enough that the neck can support the head and allow for many small and precise movements of the trunk, the ears, and the tusks. The brain is small for an animal of this size, but elephants are quick learners, have an excellent memory, and are one of the smartest animals.
Elephant’s foot by sboofek, Getty Images
Elephants foot tread by skynavin, Getty Images
While small animals, such as ants, can hang on to a vertical surface, elephants require a solid set of legs to stand and walk on. They actually stand on the tips of their toes, located along the front edge of the foot. The center and back of the foot is one large pad behind and under the toes that cushions each step and helps to carry their weight. The large, round flat of the foot spreads the weight evenly over a larger area, and their soles have treads to provide traction on slippery or uneven surfaces.
Elephant ears by Harvey Sapir, Pexels
Heat from the sun, and from the exertion of the muscles performing under the tremendous weight of the body, must be dissipated efficiently. This task is handled by the elephant’s ears, which are very large and very thin. Hundreds of blood vessels run through each ear close to the skin to radiate heat away from the body. The blood, now cooled, can be circulated throughout the body. Skin over the rest of the body is thicker, but there is little to no fat underneath, nor is there any fur or hair covering the outside to trap heat. The skin also has many wrinkles creating much more surface area than smooth skin, allowing more heat to be lost to cooler air and water.
Dirt shower by kikatani, Pixabay
Celery anyone…by eugen_z, Getty Images
An elephant’s trunk is a nose-arm-hand all wrapped into one. They can pick up large and heavy objects as well as being able to manipulate the sensitive tip to grab tiny and delicate objects. To help control the heat, they often will suck in a trunkful of water and using the end of the trunk like a shower head, spray all of the water across their body to wet down and cool off. Similarly, they can snuffle up a load of dust to spray across dry or wet skin to create a coating to help keep away biting insects and provide protection from the sun.
Elephants are built to move easily and efficiently in their environment, and they have several methods and adaptations to deal with their size and the heat. Next week we will discover more about family life and the lands they live in.
The Elephant Trunk
An elephant’s trunk is an amazing body part. It is a 300 pound nose-arm-hand about seven feet long. It contains 50,000 muscles, but no bones or cartilage, making it strong and flexible. A vast array of nerves controls it. Elephants use their trunks for a variety of tasks including: • smelling an approaching rainstorm from 150 miles away • locating food by smell including grass, branches, and fruit • lifting objects up to 400 pounds • reaching food 20 feet off the ground • using it as a snorkel when swimming underwater • using the top and bottom lip to pick up a single seed off the ground • sucking up to 2.5 gallons of water and squirting it into their mouths • sucking up water to squirt over their backs to cool off • curling it around large quantities of food to place in their mouths • controlling the shape and size of the nostril to modulate sounds • snorting dirt to spray over their backs • picking up and throwing objects in defense • entwining with another’s trunk for a friendly hug
Sloth, a word used in English for over 400 years to mean slow, was used in the 17th century to name six species of slow-moving mammals native to the tropical rainforests of Central America and northern South America. Those in the genus Choloepus have two toes on their forelimbs and include Linnaeus’s two-toed sloth, Choloepus didactylus, and Hoffman’s two-toed sloth, Choloepus hoffmanni. In a second genus, Bradypus, they have three toes on their forelimbs and include the pygmy three-toed sloth, Bradypus pygmaeus, the maned sloth, Bradypus torquatus, the pale-throated sloth, Bradypus tridactylus, and the brown-throated sloth, Bradypus variegatus.
Hoffmann’s two-toed sloth, Choloepus hoffmanni, by Leyo, Jul 2008
Linnaeus’s two-toed sloth, Choloepus didactylus, at London Zoo by Dick Culbert, Nov 2007
Sloths are 24″ to 30″ in length, weighing 8-17 pounds. They have rounded heads with tiny ears, and their forelimbs are almost twice as long as their hind limbs. Three-toed species have a small, stubby tail. Limbs are adapted for hanging and grasping, while strong claws help to support the weight of the animal. About half their body weight is from the undigested food in their stomach, which is constantly filled. Sloths have an unusual number of vertebrae in their necks, either six or nine compared to most mammal species that have seven. This allows them to almost look backwards, being able to turn through a 270˚ arc.
The most common sloth is the Brown-throated sloth, Bradypus variegatus, shown here in its native habitat at Cahuita National Park in southeast Costa Rica… by Christian Mehlführer, Feb 2007
Everything about the sloth is slow: their daily routine, their feeding, their movements, and their metabolism. They are nocturnal, eating at night and spending most of the day hanging motionless, while sleeping. Their low-energy, leaf-based diet supports a slow-paced lifestyle. Sloths are primarily folivores, feeding on leaves and fruit of several tree species. They have a multi-chambered stomach with symbiotic bacteria to help digest fibrous vegetation in a slow process that can take several weeks to fully process a single meal.
Pale-throated sloth, Bradypus tridactylus, by Fernando Flores, Apr 2013
Pygmy three-toed sloth, Bradypus pygmaeus, by Bernal Saborio, Jan 2017
Sloths move very slowly, even when threatened, averaging just 13′ a minute. They rarely leave their arboreal habitat, except to defecate. This happens only once every eight days, when they go down to the ground. They are extremely awkward and exposed during these short periods. However, sloths are agile swimmers and often use this ability to move between locations. Having a low metabolism allows them to hold their breath underwater for up to 40 minutes. Slow movements also provide protection from predators that hunt by sight, looking for movement among the trees, including ocelots, jaguars, and harpy eagles.
Observe the tint of the green algae in the hair of this three-toed sloth, genus Bradypus, by HenryAlien, Aug 2008
Sloths have long, shaggy hair that is home to a host of other organisms. Each strand is grooved, able to retain rain water, and hosts a symbiotic green algae. The algae gets shelter and water from the hair and provides nutrients to its host by absorption through the sloth’s skin. The algae is also a source of food for several other species including mosquitos, ticks, mites, beetles, and several moth species whose entire lifecycle depends on sloths. When a sloth goes down to the forest floor to defecate, female moths lay their eggs in the dung. Moth larvae feed and pupate in the dung, leaving several months later to fly up into the trees to find a mate in the sloth’s hair and begin a new cycle of life.
It is easy to imagine the grasping and defensive possibilities presented by these claws of Linnaeus’s two-toed sloth, Choloepus didactylus, by Andy, Dec 2018
Sloths have several predators, but their long, sharp claws make formidable weapons if they are attacked. However, their biggest threats come from poaching, deforestation, and electric wires as more forest acreage is being opened to development. Habitat destruction is a serious threat to the world’s rainforests, and supporting efforts to slow down or stop this process provides the best assistance for sloths and other rainforest species. You can observe these unique and interesting animals at many zoos, or learn more at your local natural history museum, including the South American display at the Jurica-Suchy Nature Museum at Benedictine University.
