Day 15 of 100 Days of Blogging
Bird migration is a fascinating phenomenon and thanks to advances in technology, scientists are finding new ways to mine information. Today’s post is a random collection of facts from a variety of studies on bird migration.
#1. Fall back, spring forward!
Migrating birds fly slower during fall migration. In spring, birds are in a hurry to get to their breeding grounds and so, not only fly faster but also make fewer stopovers. These conclusions came thanks to a study where scientists were able tap into data gathered using recently upgraded government radar stations. The upgrades made it possible to study the movements of millions of birds in a night; this compared to previous studies that might have looked at only hundreds of individuals at a time.
#2. Birds have commuter stress too!
A study conducted with Dark-eyed Juncos concluded that the stress of a migratory lifestyle can reduce a bird’s lifespan. Using DNA analysis, researches discovered the migratory juncos aged more rapidly than their resident counterparts.
#3. Zoom Zoom Zoom
Males birds on average fly faster than females during migration. This was only one of the many conclusions of a study tracking Wood Thrushes over several years. All thanks to a tiny dime-sized geolocator fitted to the birds’ backs. The first such multi-year study, it showed that songbirds keep to strict spring migration schedules and that some depart on precisely the same date year after year.
#4. We won’t leave the light on for you!
Previous research on how nocturnal migrants are affected by artificial light has focused on tall urban structures such as skyscrapers or communication towers Now, a new study has concluded that ground level sources of artificial light also influenced migratory patterns. Street lights, porch lights and even car headlamps were all mentioned as possible sources of disruption to migratory patterns. The technology in this case was fairly simple. Researchers used microphones pointed at the night sky to record and study bird flight calls.
#5. Small bird, big trip!
Ruby-throated Hummingbirds are capable of flying more than 2,000 kilometres without a break. In this case the conclusions were gleaned from more traditional bird banding techniques.
#6. Location, Location, Location
Researchers determined that birds choose their stop-over habitat based on its likelihood to offer protective cover from predators such as hawks. So lots of dense shrubbery in, open fields out. However, as the migratory journey wears on, the travellers are likely to take more risks and compromise safety for the sake of a chance to fill up on high energy food. This study also relied on more traditional banding methods.
#7 Are we there yet?
The Blackpoll Warbler holds the record for the longest nonstop, overwater flight ever recorded for a songbird. These forest dwellers make a transoceanic voyage from their summer breeding grounds in eastern Canada to South America. This requires a 3-day non-stop leg over water and covers a total distance of 2,270 to 2,770 km. The Warbler also has stopovers in Puerto Rico, Cuba and the Greater Antilles before arriving in northern Venezuela and Colombia. This research was conducted using data from geolocators and helped confirm a long held theory that, in contrast to a more land based route usually followed in Spring, this warbler follows an overwater path during autumn migration.
#8 Go west!
A study tracking Red-necked Phalaropes from Scotland’s Shetland Islands discovered the birds made an astounding 22,000 kilometre round-trip. Researchers determined that the birds followed a westbound departure route from the North Isle of Fetlar over to Iceland and Greenland, then a southbound turn brought them along the east coast of North America. Finally, heading southwest over the Caribbean and Central America toward the Pacific, the birds set down to winter on the coasts of Ecuador and Peru . The route is reversed in the spring. Although this is not the longest migration, it is the only known westward migration to the Pacific against prevailing winds. This was another case where geolocators confirmed longtime speculation over the bird’s exact migration route.
#9 The avian version of a Frequent Flyer Elite Card holder
The Arctic Tern makes an incredible journey from the Arctic to the Antarctic every year. Researchers in 2010 discovered that terns travelled about 71,000km round trip from Greenland and North America to their wintering grounds in Antarctica. Even more incredible, with a possible life span of 34 years that works out to three trips to the moon and back! Interestingly, on the return trip the birds fly an s-shaped detour route in order to take advantage of prevailing winds, and thereby reduce energy expenditure. At the same time, this means that they extend the distance travelled by several thousand kilometres. This research also made possible by the use of geolocators.
#10 But the Award goes to…
The record for the longest ever round-trip flight is held by an Arctic Tern that flew 96,000 km between the Farne Islands on the Northumberland coast and the Weddell Sea off Antarctica. Again, this would not have been possible to track without the aid of geolocators.