Tag Archives: migration

Craniac Country: Nebraska’s Sandhill Crane Migration

Two girls in a jeep rumble around the country roads of Nebraska to check out the spring sandhill crane migration and can’t believe their eyes. Be careful. Watching this might make you a craniac.

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Migratory birds prefer organic

Going organic isn’t just a popular choice for eco-savvy dieters, turns out migratory birds like it too. A new study out of Lund University in Sweden shows that migrating birds lean towards green when it comes to large-scale monoculture farms, with higher abundances and diversity of birds choosing to stop at organic farms than conventional ones. The findings offer new crops for thought when it comes to managing agriculture for wildlife well-being.

The idea that organic farming is good for wildlife is nothing new. Farming practices that hit overdrive and heavy pesticide use have been linked to drops in wildlife populations. But previous studies focused largely on bugs or resident bird populations. Juliana Dänhardt and Martin Green of Lund University decided to take the research a step further, focusing on migratory bird species.

Migratory birds get hit with a double whammy when dealing with environmental stress. They contend with a lot of the same environmental pressures as resident birds, but enjoy the added baggage that comes from moving into a temporary living situation. These visitors tend to show up at tilling time to an unfamiliar landscape and must fuel up in a hurry before embarking on the next leg of their journey.

Dänhardt and Green wanted to see if organic farming and more diverse cropland would helped alleviate some of these pressures. In 2005, they and their team selected a dozen pairs of farms in Falsterbo, Sweden, one of the richest agricultural regions of the country. The pairs were set up to compare organic versus conventional and diverse versus simple crop farms. During the fall migratory season, they conducted bird surveys to see what happened. Dänhardt and her colleagues found the relationship between birds and farm preference to be a complicated one.

The strength of bird populations was all over the show. Some types of birds did prefer diverse organic farmland, while others were less discerning. And certain species, such as geese and golden plovers, showed a penchant for wide-open monoculture fields. But one overarching trend did emerge from the complexity. Turns out, birds that chose the wide-open fields also preferred the organic version.

At the moment, ag trends in Sweden lean towards encouraging crop diversity as a way to bolster wildlife populations, but this study indicates that supporting organic or low-impact farming practices on large-scale monoculture farms could be another method for helping out those hard-flying, fast-eating, stressed out migratory birds.

The study is published in the online early edition of the journal Oikos.


The Mangrove Forests of Mexico’s Yucatan Peninsula

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Along the Yucatan Peninsula, in a land of heat and drenching humidity thrives a rare mangrove ecosystem, important for coastal life and home to jaguarundi, hundreds of bird species and, yes, maybe a mosquito or two.  I hope you enjoy this short jaunt into the mangroves, sans the mosquitoes, near Celestun in Mexico’s Yucatan Peninsula. One afternoon doesn’t do a place like this justice, but it is a glimpse into this vulnerable ecosystem that is increasingly under threat from climate change, deforestation, pollution and coral reef degradation.


Lady bug swarm turns Green Mountain red

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Lady bugs unite! When a friend of mine posted some photos she took while on a hike on Boulder’s Green Mountain, I couldn’t believe my eyes. I saw entire tree trunks covered in red. The red was lady bugs, a mass gathering of a gardener’s best friend, as they search for mates and prepare to hibernate for the winter. Now this was something I had to see for myself.

Of course, not everyone can make the hike to Green Mountain, but hopefully you can live a little vicariously through this slide show, and learn a little something new about this “cuter” member of bug-dom.

There are more than 400 species of lady bugs, (or as they’re more officially known ladybird beetles), in North America. This year has been an unusual one for lots of natural phenomena in Colorado — a wet, cool summer has led to an endless green summer and multitudes of wildflowers — and this year’s lady bug gathering is no exception. Boulder Open Space and Mountain Parks estimates that this could be a record-setting year for the annual swarm.

Besides the slideshow, I’ve made a little list of interesting lady bug facts you might not know.

  • They’re cannibals.
    • at least during their larval stage. Researchers recently discovered lady bug babies hatch and eat their siblings. Don’t get too disillusioned. They grow out of it.
  • They don’t change their spots.
    • Some people think you can tell the beetle’s age by the number of its spots, but according to the Boulder Open Space and Mountain Parks, you keep what you’re born with when it comes to the dots.
  • They “play dead.”
    • If an adult ladybug feels threatened it will fall down and “die,” or let off a foul yellow ooze from its leg joints that most animals won’t want to eat, (University of Arizona)

Bait fisheries drive decline of bird species

(Photo/Andrew Easton, 2004)

(Photo/Andrew Easton, 2004)

Every year the horseshoe crabs gather to spawn, releasing thousands of eggs along the Delaware Bay coast. And with timing perfected by evolution, red knots, a bird enduring one of the most impressive yearly migrations from the Arctic to the Tierra del Fuego, arrive just in time to gorge on the eggs of the horseshoe crab. It is a vital stop on the “peeps'” spring migration. But the crabs and their eggs are disappearing, a loss with dire consequences for the little birds.

Red knot populations have fallen more than 75 percent in recent years, and new research published in this month’s issue of Bioscience reveals that Red knots can thank the bait fisheries for their hungry stomachs. Within half a decade the fisheries harvesting horseshoe crabs grew 20-fold, gobbling up more than 2 million crabs a year and effectively eliminating 90 percent of the eggs that red knots rely upon to survive their almost 19,000 mile migration.

But this research is not just a blame game for the fisheries. A coalition of scientists worked together on this study to help draft recommendations for the adaptive management of the bait fisheries that could help all three groups survive.


Family dining right whale style

 

For a month after birth, Southern right whale mothers and their calves rest and nurse. Then, like the pair shown here off Argentina, they start to swim faster and farther as they prepare for a long migration in the South Atlantic to reach their feeding areas. A University of Utah study found mother whales teach their calves where to eat, raising concern about whether the whales can adapt as global warming disrupts feeding grounds. (Photo/John Atkinson, Ocean Alliance)

For a month after birth, Southern right whale mothers and their calves rest and nurse. Then, like the pair shown here off Argentina, they start to swim faster and farther as they prepare for a long migration in the South Atlantic to reach their feeding areas. A University of Utah study found mother whales teach their calves where to eat, raising concern about whether the whales can adapt as global warming disrupts feeding grounds. (Photo/John Atkinson, Ocean Alliance)

Mom right whales know best when it comes to mealtime it seems. They lead calves to grub at traditional feeding grounds teaching their offspring generations of knowledge about when and where to find food. In fact whole clans of whales will dine together in the cetacean version of a family-owned dining spot. But this is one family tradition that could lead to starvation for an already vulnerable whale species if climate change causes shifts in food distribution.

Previous research by Vicky Rowntree, research associate professor of biology and a coauthor of the new study at the University of Utah, has already shown the impacts of climate change on right whale populations. When sea temperatures rise, krill disappear and right whales respond by giving birth to fewer offspring. Now these new studies into whale behavior could highlight another problem for the whales when it comes to food.

“A primary concern is, what are whales going to do with global warming, which may change the location and abundance of their prey?” asked Rowntree in a press release. “Can they adapt if they learn from their mother where to feed – or will they die?”

Rowntree and her colleagues collected skin samples from right whales and, using a novel technique in science, combined DNA and isotope analysis to determine whale lineages and where they tend to chow down. They found that related whales congregated in designated areas to feed, and that mothers teach calves in their first year of life where to find food.

Here’s to hoping that right whales will be quick to adapt if the buffet moves elsewhere.


The Nature Files and a visit to Sawhill Ponds

The Nature Files brings information about the open spaces and wildlife that share our home in the Denver Metro area to you. I hope that this site can be a resource as well as an inspiration for those of you wanting to explore the nature in your backyard. I will periodically upload featurettes including sights and sounds of easy day or weekend outings around Boulder, Denver and other nearby counties, and will also share photos, or news about what’s happening with parks and open spaces.

Click photo to view a short video about Sawhill Ponds.

Click photo to view a short video about Sawhill Ponds.

SAWHILL PONDS

I hope you enjoy the first posting about Boulder’s Sawhill Ponds, a series of 18 ponds — reclaimed gravel pits — that are a safe haven for birds and other local wildlife. This open space area is about half a mile north of the 75th Street and Valmont Road intersection, and great for an easy, but not too crowded nature walk. I plan to bring you a new featurette about this location each season in order to give you some idea of how this environment evolves throughout the year. Click on the photo below to access the first show depicting late fall at Sawhill Ponds.


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