Conserve Wildlife Blog

Archive for the ‘Beach Nesting Birds’ Category

Mapping red knots in the Arctic

Friday, August 3rd, 2018

A new study investigates the habitat preferences of endangered Red Knots in their vast, remote Arctic breeding range. Credit: M. Peck for Phys.org

by The American Ornithological Society, via Phys.org

Rutgers University’s Richard Lathrop, Conserve Wildlife Foundation of New Jersey’s Larry Niles, and their colleagues attached radio tags to 365 knots captured while migrating through Delaware Bay in 1999-2006. To learn where and in what sort of habitat the tagged birds nested, they then conducted surveys via small airplane across the south and central Canadian Arctic, a vast study area spanning from Victoria Island in the west to Baffin Island in the east.

The study shows that there are more than 74,000 square kilometers of suitable rufa Red Knot habitat across their Central Arctic breeding range—enough space for at least that many breeding pairs, assuming one square kilometer of territory per nest.

Click here to read more.

Birds in better condition than last year but still face an ecological roulette

Wednesday, July 11th, 2018

by Larry Niles (Part 3 of 3)

With the stopover period winding down, we can say the red knot and other shorebird species left the bay in better condition than the disastrous condition of last year. So what does it mean?

First, the last four years have been a sort of ecological roulette for the birds. Horseshoe crab numbers remained at only 1/3 the potential population possible on Delaware Bay leaving birds at the mercy of good conditions to get enough eggs. Last year, water temperatures stayed low during the mid-May depressing the spawn and the density of eggs. Although the average was 8000-eggs/square meter, there were less than 2000 eggs/ meters square in the month of May. (more…)

Good horseshoe crab egg densities draw 34,500 Red Knots to the bay

Monday, July 9th, 2018

by Larry Niles (Part 2 of 3)

The best news is a direct consequence of these good conditions, the number of knots and turnstones increased this year. Our season-high estimates show that there are 34,500 knots in the bay and 21,000 ruddy turnstones. These may be the highest counts on the bay in at least 15 years.

Why? At first one would conclude the increased numbers on the bay represent a real increase in the size of the population, but it is not. Shorebirds need time to respond to improving conditions because they are relatively slow breeders, as are most Arctic breeders. Knot numbers on Delaware Bay basically depend on the availability of crab eggs. In bad years, numbers go down because birds come to the bay and leave quickly. (more…)

Horseshoe crabs expanded breeding into neap tides

Saturday, July 7th, 2018

by Larry Niles (Part 1 of 3)

The horseshoe crabs extended their breeding period into the neap tide phase after the cold weather of mid-May decreased water temperature during the spring tides.  The crabs roughly require a water temperature of about 59 degrees F before breeding begins in earnest.  Crabs still breed at a lower temperature, but many more will breed above the temperature threshold.

At the same time, crabs also look for spring tides, the higher high tides that come with full and new moons, because they can breed in sandy places unavailable at lower tides. This year the water cooled during the new moon spring tide and warmed in the neap.  Good spawning during the neap tides of the last week was welcome good news.  This May good spawning conditions will raise average egg densities about 50% higher than last year. (more…)

Tierra del Fuego: The View from Above

Saturday, March 24th, 2018

Just above and to the right of the plane shadow, thousands of shorebirds gather. Photo by Joe Smith

CWF scientists recently returned from a trip to Tierra del Fuego where they studied red knots and other migratory shorebirds that spend the month of May at New Jersey’s Delaware Bayshore.

CWF consultant Joe Smith captured some incredible aerial images of the coastline holding a flock of thousands of shorebirds in his blog story. See more photos of the flock and read Joe’s introductory overview about the trip here. Stay tuned for more installments about this vital trip.

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