Conserve Wildlife Blog

Posts Tagged ‘migration’

Band Resighting Sheds New Light on Delaware Bay Oystercatcher Population

Thursday, December 14th, 2023

When CWF began monitoring American oystercatchers nesting on the Delaware Bay this past spring, we also set out to place field-readable bands on as many oystercatcher adults and chicks as logistically possible. Band resights allow biologists to collect a wealth of information about site fidelity, habitat use, dispersal, and migration, especially when data is collected over many years. Since the Delaware Bay population of oystercatchers was previously unmonitored, we have a lot to learn about their life histories and how they may differ from other oystercatchers in the state, if at all. Where are these birds staging and wintering? Do breeding adults return to the same mates and nesting locations each year? Where do fledged chicks disperse, and will they return to their natal grounds on the Delaware Bay to breed upon reaching sexual maturity? Banding efforts, combined with resight data reported by biologists, dedicated volunteers, and the general public will help answer these questions (and more) as we increase the number of marked individuals on the Bayshore.

Orange C41 (aka “Crouton”) being equipped with a metal federal band on the lower leg. The color of the field-reable bands on the upper legs represents which state the bird was banded in (New Jersey and New York use orange), while the alphanumeric code on the band is unique to the individual bird. All handling of birds is conducted by trained individuals under proper permits.
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Happy Amphibian Week!

Tuesday, May 9th, 2023

by Christine Healy, Wildlife Biologist

If you follow us or any other wildlife organizations on social media, you may have noticed that our posts these last few days have been inundated with amphibians. It may seem like odd timing, given that our early breeders (wood frogs, spotted, and Jefferson salamanders) completed their crossroad migration last month. But the reason is simple – it’s Amphibian Week!

Close up of an American toad that hitched a ride during this year’s crossing. Photo Credit: Nikki Griffiths

Globally, amphibians are disappearing faster than any other vertebrate group. The International Union for the Conservation of Nature (IUCN) estimates that 41% of amphibian species categorized for their Red List are currently facing extinction. That estimate is likely conservative, given that these creatures are often small and difficult to survey, rendering many species data deficient. This is concerning from multiple perspectives. From an ethical standpoint, we don’t want any wildlife to go extinct except maybe, in my extremely biased opinion, certain types of ticks… (I began my career as a moose technician and saw firsthand the terrible consequences that winter ticks have on these behemoths). Beyond that though, amphibians are tasked with a lot of responsibilities and carry out their work efficiently and without complaint. The list is inexhaustive but here are a few things that amphibians are doing for us and our planet as we speak: filtering water, sequestering carbon, eating pests (like mosquitos!), serving as prey for countless predators, helping researchers study regeneration (with hopeful applications to the future of organ transplants), aerating the soil in your garden,  indicating where water sources have been contaminated by pollutants, and giving everyone who meets them a reason to smile.

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CWF Book Club: Winter Reading List

Monday, January 9th, 2023

Meaghan’s Recommendations

by Meaghan Lyon, Wildlife Biologist

The cold and dreary winter weather makes for the perfect excuse to curl up with a book. Reading a good book can transport you into new worlds, or, in the case of the following books I’m about to recommend, help you get excited about getting outside to explore your own winter wildland.

My first recommendation is a Field Guide, Tracking and the Art of Seeing: How to Read Animal Tracks and Sign written by Paul Rezendes. Although this is a field guide to tracking wildlife, this book includes personal accounts that make it much more readable cover to cover. The author includes several North American species including rodents, hoofed animals, bears, raccoons, opossums, and members of the weasel, rabbit, dog, and cat families. He describes not only the signs these animals leave but also their ways of life throughout the seasons to help the reader get a fuller picture.

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The Mighty Migration of the Magnificent Monarch

Saturday, November 21st, 2020

by Mary Emich, Assistant Biologist

Monarch butterfly refueling in Cape May as it prepares for fall migration to Mexico.
Photo courtesy of Lindsey Brendel.

Over the last decade, the monarch butterfly, Danaus plexippus, population has declined. Climate change has affected weather conditions, the winters are colder and wetter while the summers are hot and drier. This disturbs their survival rate, especially during their long annual migration. Other factors like pesticides and a loss of habitat to human development further threaten the monarch population.

The monarch butterfly migration is mysterious and magnificent. Every fall season, monarch butterflies travel thousands of miles from their breeding grounds in the United States and Canada to escape the cold winters. Monarchs in Eastern North America spend the winter months in the Transverse Neo-Volcanic Mountain Range in Michoacan, Mexico. To reach their destination, monarch butterflies migrate over 3,000 miles, utilizing the air currents and making many stops along the way.

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Red knot decline confirmed by CWF research highlighted in NY Times

Friday, June 12th, 2020
Photo by Hans Hillewaert

Conserve Wildlife Foundation’s research with scientist Dr. Larry Niles was highlighted in today’s New York Times feature detailing the 80 percent decline in red knots in New Jersey’s Delaware Bay this spring.


by Jon Hurdle, The New York Times

A sudden drop in the number of red knots visiting the beaches of Delaware Bay during migration this spring has renewed concern among scientists about the survival of the threatened shore bird’s Atlantic Coast population.

According to biologists, the number of knots that stayed to feed at the bay in May declined by about 80 percent from the same time last year. The Delaware Bay is one of the world’s most important sites for shorebird migration.

Continue reading at nytimes.com.