Animal Flight Reveals Design Wonders

Photo: An eastern towhee, near Shenandoah National Park, via Flickr.

Many articles on Evolution News require the unsavory but necessary task of responding to the false scientific claims of evolutionists and correcting the distortions of materialists who deny the reality of intelligent design. One thing we can all celebrate, however, is pure scientific discovery.

Design advocates appreciate the thousands of field scientists who go out into the wild with instruments to measure things. It’s a unique human trait that reflects our own design and purpose: the desire to discover, know and understand how things work. Sometimes field scientists veer off course to attribute their discoveries to blind chance, but these afterthoughts can be dissolved from the data like tarnishing the silver, revealing the luster beneath. Here are some recent discoveries about animals that fly.

bird migration

Illustra’s Documentary Viewers Flight remember how geotagging revealed the detailed flight paths of arctic terns. In the years following Carsten Egevang’s groundbreaking research, the number of geologists steadily dwindled as engineers found ways to fit more instruments into smaller devices. These, in turn, can be attached to smaller birds, increasing our knowledge of more species.

Corryn Wetzel reports to new scientist on tiny trackers smaller than a jellybean that reveal the migration routes of birds in astonishing detail. Shelley Eshleman is part of a research team for the Williston Conservation Trust in Pennsylvania. Wetzel followed her into the woods to see how she catches eastern towhee (pictured above) and other species in soft wisps of mist, then teams them with the loggers.

This little bean is an ultra-lightweight radio”nano tag”, and Eshleman is one of a handful of scientists pioneering their use to map bird locations. All (Pipilo erythrophthalmus) that she began tagging this summer are among the first of their kind to be tracked in this way. Unlike traditional radio trackers, which are too heavy for starling-sized birds like towhi, the tags used in what’s called the Motus Wildlife Tracking System can weigh as little as a few drops of rain.

“Where Motus excels is able to tag and track the smallest animals over the greatest distancessays Stu Mackenzie of Birds Canada in Ontario, who pioneered the use of the technology. [Emphasis added.]

The new system does not require recapturing the birds as the tags eventually fall off without damage. Stations up to 15 km away can track birds. With 115 stations operating from Maryland to Maine, and more on the way in other countries, the team collects billions of data points and shares them online. A video in the article shows field scientists tagging individual birds and displays some of the migratory tracks followed so far on a map. This information on 287 species to date, including owls, “is starting to revolutionize the way we track migratory species – and the level of detail we can gather about them.”

Magnetic direction

Scientists still don’t understand how animals use the Earth’s magnetic field to navigate. The ability is found in birds, insects, reptiles (sea turtles) and fish. News from the University of Oldenburg in Germany reminds us how marvelous it is:

Professor Henrik Mouritsen, who leads the Neurosensory Science Research Group at the University of Oldenburg, points out a particularly surprising aspect this phenomenon: “Most songbirds migrate at night. Young birds that have never traveled this route before migrate alone, without parents or siblings,” he explains. Wheatear — cute little songbirds that weighs only 25 grams — cover distances of up to 15,000 kilometers per year. “Their navigation systems are incredibly accurate. Experienced migratory birds can find their way home exactly the same burrow they used to breed the previous year after traveling thousands of miles“, explains the biologist. The big question for Mouritsen is how they do exactly that – with a brain that in most cases weighs less than a gram.

Mouritsen’s team investigated the hypothesis that animals experience a quantum mechanical effect – the momentary formation of radical pairs in light-sensitive cryptochrome proteins – as data for magnetoreception. How the animal perceives and uses this information is still unknown. It could be one of many entries into animal navigation systems.

There have been many indications over the years that birds do not rely on a single source of information on their long journey. In addition to stars and Landmarksit is likely that migratory birds use both trajectory of the sun and their smell to orient. And they probably a second, even more mysterious magnetic sensor in their beakwhich may consist of small crystals of iron and allows them to use the magnetic field like a map for browsing. This mechanism is being explored in other Collaborative Research Center sub-projects.

After many years of trying to figure this out, a scientific explanation of the wonder of animal magnetic navigation is still in progress. Imagine what that means; small songbirds weighing barely a few grams challenge the greatest thinkers of biophysics. Learn more about this mystery in Eric Cassell’s recent book, Animal algorithms.

Bat Balance

Those who enjoyed Michael Denton’s book The miracle of man remember the question of thermoregulation: how animals avoid freezing or overheating. Thermoregulation is essential for both cold-blooded and warm-blooded animals, and each type uses internal mechanisms for this. Capacity also relies, Denton shows, on the prior suitability of the environment: finely tuned factors such as sunlight, atmosphere and water properties. Humans have an exceptional capacity for evaporative cooling through the sweat glands, as shown in the video “The Wonder of Water”, based on Denton’s book with this title:

Bats are small, warm-blooded mammals that also have to solve the problem of thermoregulation. According to news from McGill University, no matter what climate they live in, these “small but mighty” flyers achieve “the perfect balance between flight costs and heat dissipation.” Somehow they achieve the optimum by breaking the rules.

Many species of mammals living in cold climates tend to have large bodies and short limbs to reduce heat loss – a general pattern known as Bergmann’s rule. However, bats are the exception to the rule, displaying small body sizes in both hot and cold regions. A McGill-led team of researchers is shedding light on this longstanding bat size debate and focusing on why bats apparently do not conform to ecogeographical patterns found in other mammals.

Partial answers have come from measurements of wing area and body mass in many species of bats. This data was fed into computer models that took into account the energy costs of the flight.

The team performed an analysis of the wing surface area to mass ratio in nearly 300 species of bats and their results confirmed the model’s prediction that the shape of the body evolves towards an optimal ratio. High surface areas relative to body mass increase heat dissipation rates and therefore the cost of maintain optimal body temperaturewhile high body mass increases the cost of flight.

Scientists have attributed this successful cost-benefit accounting to “selective forces”, but our readers know better. Optimization is smart design in action.

Insect Convention

UK field scientists working in Cyprus were stunned. They were caught in a swarm of migrating insects. News from the University of Exeter describes the scene as 6,000 insects per meter per minute passed by them.

“I had never seen anything like it,” said lead researcher Will Hawkes, a PhD student at the Center for Ecology and Conservation at the University of Exeter’s Penryn Campus in Cornwall.

The sky was black with insects and we were bombarded by migrating flies, so much so that we had to take shelter behind the car door.

They estimate that 39 million insects passed through this corridor in northeast Cyprus en route from the Middle East to Europe. One of the biggest surprises for the team was the “sheer diversity of species” participating in this gathering: dragonflies, painted lady butterflies, locusts, etc. The vast majority (86%) were fly types. But perhaps the greatest wonder is how these tiny flyers were able to cross nearly 70 miles of open seas on their journey.

To confirm whether the insects indeed migrate at high altitude above the field site, further investigations using entomological radar are needed. Additionally, although it is not possible for us to accurately predict the magnitude of the migration, we have made estimates based on different lengths of potential migration fronts leaving the Middle East coast; these indicate that the total biological flux of insects leaving the Syrian and/or Israeli coastline was probably on the order of hundreds of millions, and possibly billions of individuals.

Open access writing in Ecogeography, quoted above, focuses primarily on ecological and conservation issues. But one has to wonder how navigational systems, aerodynamic systems and sensory systems can be fitted into such tiny animals. What I would like to know is how a tiny insect that I can’t even see manages to aim for my face in the dark at night.

This is the end of this episode of impressive things that fly. These stories all show that fieldwork on animal flight has much more to discover.

Comments are closed.