Conserve Wildlife Blog

July 13th, 2018

Photos From The Field

NJ Eagle Chicks Spread their wings and fly.

by Larissa Smith; CWF biologist

So far this season 123 eagle chicks have fledged (taken their first flight). Even after fledging the chicks will stay around the nest area for the next few weeks learning to hunt, fly and survive on their own.

Below are some photos of recent fledges taken by NJ Eagle Project Volunteers

Navesink fledge 6/27/18@Randy Lubischer

Princeton 7/10/18@Kevin & Karin Buynie

Edison 6/11/18@ Kevin Redden

Kettle Creek 6/12/18@ Alex Tongas

Manville 7/12/18@Rose Joy

Sadie’s Lane 6/7/18@M.Tribulski

July 11th, 2018

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

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.

This year, the weather and water temperature added to a good spawn in May and the birds appeared to have left in good condition. Unfortunately, it’s only chance. If bad weather or cool temperatures return, they will face another bad year. We need more crabs to smooth out the rough years. The bay can support three times the current number.

An increase in the number of horseshoe crabs would transform the bay. In 1990 and 1991, we had three times the number of crabs we have now. But we had 10 times the density of eggs because of multiple breedings by females and more eggs reaching the surface as one crab digs up another’s eggs. Additionally, it lasted for two months, unlike this year’s eggs, which lasted only a few weeks.

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years. Read the paper that describes the work of a team of scientists measuring egg densities in 1991 before the overharvest of crabs here.

Red Knot over 180g ready to leave the bay for the Arctic breeding grounds. Photo by Stephanie Feigin.

July 9th, 2018

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

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.

This was the case last year. Egg densities during May plummeted to less than a few thousand-eggs/meter2.  Knots banded in Delaware Bay were resighted days after release in other stopovers like Cape Cod. Consequently, our Red Knot count on the bay fell from 24,500 in 2016 to 17,500 in 2018. We assumed this was not a real decrease in numbers, but the result of birds leaving right after finding eggs too scarce or competition too intense on the bay.

This year we found good egg densities, and birds staying long enough to be counted. The aerial and ground counts detect only a portion of that number depending on the total number of red knots and the egg density. The longer birds stay, the greater the proportions of the total are seen on one day. So this year we had good egg densities, good weights, and good numbers. It was one of the best of seasons in recent memory.

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

A red knot flock near Straight Creek on Egg Island in NJ. This flock was one of several on Egg island that totaled over 13,000, a third of the entire bay flock. The birds use this remote marsh as a staging site before flying off to the Arctic.

Shorebirds on Cooks Creek Inlet seen from Cooks Beach. The birds practically reside in this inlet and the four others that flow from the marsh behind the beaches from Reeds Beach to Pierce’s Point.

July 7th, 2018

Horseshoe crabs expanded breeding into neap tides

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.

We found eggs lying on the beach in many beaches including Reeds Beach at the Jetty.  This is better news then it first appears.  Last year shorebirds desperately fed on the eggs at the jetty and beach corner at North Reeds to the delight of many visitors.  Little did they know, the birds couldn’t find eggs elsewhere at similar densities and would have avoided the place if they could. The good news this year is they have.

Higher egg densities on the New Jersey’s Delaware Bayshore gave shorebirds a welcome boost.  Most gained weight rapidly.  The weights of red knots and ruddy turnstones show the difference.  Knots rapidly reached the 180-gram threshold considered necessary for birds to reach the Arctic breeding areas in good conditions, and Ruddy Turnstones are in similarly good condition.

Dr. Larry Niles has led efforts to protect red knots and horseshoe crabs for over 30 years.

A view from the Reeds Jetty looking south. Horseshoe crab eggs piled up after a few days of southerly winds but unlike last year shorebirds did not pile into eat them. It a good sign. The jetty exposes the birds to intense disturbance and they would rather feed in more secure places – and they did because they could.

Horseshoe Crab breed on the sod bank of Egg Island and shorebird feed on the eggs as they are being laid. The breeding attempts must fail because eggs cannot incubate in the anoxic environment of marsh mud but its a good sign the crabs are breeding in odd places.

July 6th, 2018

Osprey Chicks Get A Necessary “Home” Upgrade

Thanks to dedicated Conserve Wildlife Foundation of NJ staff and volunteers three osprey chicks were saved from what could have been an unhappy fate.

NJ Osprey Project Volunteers Matt Tribulski, Wayne Russell and John King were surveying osprey nests in the Wildwood back bay area this past weekend. They checked on a nest with three chicks and found that the platform top was broken and a strong possibility it could collapse, especially with any heavy rains or winds. The chicks weren’t old enough to fly and would have fallen to the marsh and died.

A plan was formed and CWF biologist, Meghan Kolk joined Matt and John to replace the platform.

A new platform was assembled before going out to the nest. Once at the nest the operation needed to go quickly so as not to put additional stress on the chicks. The three chicks were carefully placed in a basket, lowered to the ground and kept in the shade of an umbrella ,while the old platform was knocked down and the new sturdy one installed.  Once the platform was ready the chicks were placed back in the nest along with some frozen fish (all this happened in under 20 minutes). Once the boats pulled away from the nest area the adult ospreys returned to the nest. This was a tragedy avoided due to the dedication of CWF volunteers and staff. THANK YOU

 

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