Many articles at Evolution News require the unsavory but necessary task of answering fake science claims by evolutionists and correcting the distortions of materialists who deny the reality of intelligent design. One thing we can all celebrate, though, is pure scientific discovery.
Design advocates appreciate the many thousands of field scientists who go out into nature with instruments to measure things. It’s a uniquely human trait that speaks to our own design and purpose: the desire to discover, to know, and to figure out how things work. Sometimes field scientists veer off course to attribute their discoveries to blind chance, but those after-the-fact opinions can be dissolved off the data like tarnish on silver, revealing the luster underneath. Here are some recent findings about animals that fly.
Viewers of Illustra’s documentary Flight remember how geologging revealed the detailed flight paths of arctic terns. In the years since Carsten Egevang’s groundbreaking research, geologgers have continued to shrink as engineers find ways to pack more instrumentation into smaller devices. Those, in turn, can be attached to smaller birds, increasing our knowledge of more species.
Corryn Wetzel reports at New Scientist about tiny trackers smaller than a jelly bean that are revealing bird migration routes in amazing 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 towhees (pictured above) and other species in gentle mist nets and then outfits them with the loggers.
That little bean is an ultra-lightweight radio “nanotag”, and Eshleman is one of a handful of scientists pioneering their use to map birds’ locations. The towhees (Pipilo erythrophthalmus) she has started tagging this summer are some of the first of their species to ever be tracked this way. Unlike traditional radio trackers, which are too heavy for starling-sized birds like towhees, the tags used in what’s known as the Motus Wildlife Tracking System can weigh as little as a few raindrops.
“Where Motus excels is being able to tag and track the smallest animals over the largest distances,” says Stu Mackenzie at Birds Canada in Ontario, which pioneered the use of the technology. [Emphasis added.]
The new system doesn’t require recapturing the birds because the tags eventually fall off without harm. Stations up to 15 km away can track the birds. With 115 stations in operation from Maryland to Maine, and more on the way in other countries, the team is collecting billions of data points and sharing it online. A video in the article shows field scientists tagging individual birds and displays some of the migratory tracks tracked so far on a map. This information on 287 species so far, including owls, “is starting to revolutionise how we track migratory species — and the level of detail we can gather about them.”
Scientists still do not 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 of what a wonder this is:
Professor Henrik Mouritsen, who heads the Neurosensory Science research group at the University of Oldenburg, points to a particularly surprising aspect of this phenomenon: “Most songbirds migrate at night. Young birds that have never flown this route before migrate alone, without their parents or siblings,” he explains. Northern Wheatears — pretty little songbirds that weigh just 25 grams — cover distances of up to 15,000 kilometres a year. “Their navigation systems are incredibly precise. Experienced migratory birds can find their way back to the exact same burrow they used for breeding the year before after travelling thousands of kilometres,” says the biologist. The big question for Mouritsen is how exactly they do this — with a brain that in most cases weighs less than a gram.
Mouritsen’s team has been investigating the hypothesis that the animals sense a quantum mechanical effect — the momentary formation of radical pairs in light-sensing cryptochrome proteins — as data for magnetoreception. How the animal perceives and uses that information is still unknown. It could be just one of several inputs into animal navigation systems.
There have been many indications over the years that the birds don’t rely on only a single source of information on their long journey. In addition to stars and landmarks, it is likely that migratory birds use both the sun’s trajectory and their sense of smell for orientation. And they probably have a second, even more mysterious magnetic sensor in their beaks, which possibly consists of tiny iron crystals and enables them to use the magnetic field like a map for navigation. This mechanism is being investigated in other subprojects within the Collaborative Research Centre.
After many years trying to figure this out, a scientific explanation for the wonder of animal magnetic navigation is still a work in progress. Imagine what this means; little songbirds weighing just a few ounces are challenging the greatest thinkers in biophysics. Learn more about this mystery in Eric Cassell’s recent book, Animal Algorithms.
Those who have been enjoying Michael Denton’s book The Miracle of Man remember the issue of thermoregulation: how animals keep from freezing or overheating. Thermoregulation is critical for both cold-blooded and warm-blooded animals, and each type employs internal mechanisms for it. The ability also relies, Denton shows, on prior fitness of the environment: finely tuned factors such as sunlight, the atmosphere, and properties of water. Humans have an exceptional ability for evaporative cooling through sweat glands, as shown in the video “The Wonder of Water,” based on Denton’s book of that title:
Bats are small warm-blooded mammals that must solve the problem of thermoregulation, too. News from McGill University says that no matter in what climates they live, these “small but mighty” flyers achieve “perfect balance between flight costs and heat dissipation.” Somehow, they reach the optimum by breaking the rules.
Many mammal species 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 long-standing debate over bats’ body sizes and focus on why bats are seemingly non-conforming to ecogeographical patterns found in other mammals.
Partial answers came from measurements of wing surface area and body mass in many species of bats. This data was fed into computer models that considered the energy costs of flight.
The team carried out an analysis of the wing surface area-to-mass ratio in close to 300 bat species and their results supported the model’s prediction that body shape evolves towards an optimal ratio. High surface areas relative to body mass increases heat dissipation rates and thus the cost of maintaining optimal body temperature, whereas a high body mass elevates the cost of flight.
The scientists attributed this successful cost-benefit accounting to “selective forces,” but our readers know better. Optimization is intelligent design in action.
Field scientists from the UK working in Cyprus were stunned. They were caught up in a swarm of migratory insects. News from the University of Exeter describes the scene as 6,000 insects per meter per minute came flying by them.
“I had never seen anything like it,” said lead researcher Will Hawkes, a PhD student from the Centre of Ecology and Conservation on University of Exeter’s Penryn Campus in Cornwall.
“The sky was dark with insects and we were being pelted by migratory flies, to the extent that we had to shelter behind the car door.”
They estimate that 39 million insects came through this corridor on northeast Cyprus on their way from the Middle East to Europe. One of the biggest surprises to the team was the “sheer diversity of species” participating in this gathering: dragonflies, painted lady butterflies, locusts, and more. The vast majority (86 percent) were types of flies. But perhaps the greatest wonder is how these tiny flyers were able to cross nearly 70 miles of open sea on their journey.
To confirm whether insects are indeed migrating at high altitude above the field site, further investigations utilising an entomological radar are needed. In addition, while it is not possible for us to accurately predict the scale of the migration, we have made some estimates based on different lengths of potential migratory fronts leaving the Middle Eastern coast; these indicate that the total bioflow of insects departing the coastline of Syria and/or Israel was probably in the hundreds of millions, and perhaps in the billions of individuals.
The open-access writeup in Ecogeography, quoted above, focuses primarily on ecological and conservation issues. But one must wonder how navigation systems, aerodynamic systems, and sensory systems can be outfitted into such tiny animals. What I would like to know is how a tiny insect I can’t even see manages to target my face in the dark at night.
That’s a wrap on this episode of awe-inspiring things that fly. These stories all show that field work on animal flight has much more to discover.