Wednesday, July 28, 2010

Yellow Warbler Extravaganza!

Each year during mid- to late July we get an influx of hatching year Yellow Warblers that mill about in pods at the Navarre Migration Station. These may be from the Navarre Ridge and marsh or from a larger region of origin. We set nets each time we run the MAPS station in July to get a sample of the youngsters banded. This allows us to put an actual age to the bird if captured again, instead of catching and banding it as an adult and having to say it is an After-second year in the spring or an After-hatch year in the fall. We captured 54 new Yellow Warblers and 26 other birds in 5.5 hours.

This time of year it is helpful to look at bill color of Yellow Warblers to assist in aging. The bill color of hatching year birds have a flesh colored lower mandible. The adult (After-hatch year) will have a bill that both mandibles are slate gray (see below with the adult on left and hatching year bird on right). **note this does not work in all species of warblers. I know that adult Prothonotary Warblers in late summer their lower mandible turns a pinkish which can make you think it may be a hatching year bird.**

Here is another yellowish bird for the summer. It is a nice comparison to its cousin the Baltimore Oriole. Both are orioles with their gray leg color and bill coloration. They are both hatching year birds with the lower mandibles not having the nice slate-gray color of the adult birds. Can you tell what sex either bird is? Unfortunately you cannot. The wing chord works for the Orchard Oriole which is the bird on the left. The bird is a male with a wing chord over 74 mm. Females are less than 74 mm. Baltimores have a sex determination using wing chord as well which says that it works “in most cases.” Hatching year males are greater than 91 mm and females are less than that. Here is the back side. Note the size differences in these species.As you can guess there would be a little overlap in wing measurements of males and females of the same species. After all, there are small and large female and male Homo sapiens.
You had better take in all the Yellow and Prothonotary Warblers and orioles you want to see this year in the next couple weeks in Ohio. They are staging up to head south. By mid-August most will be south of Lake Erie.

Friday, July 2, 2010

West Sister Temporarily Invaded by Humans

After the third try to get to the 80 acre West Sister Island which is about 9 miles north of the Magee Marsh State Wildlife Beach, banding and nest surveying crews made it to the island. Being dependent on a boat that runs and good lake traveling conditions makes it a challenge to get to the island. There are other challenges once one gets to the island. Most days it is bugs, large poison ivy trees (vines with 3 inch or better diameter standing up like a tree), unexploded ordinances, and other natural unexploded ordinances from the nests above prove to make the day very eventful. That is why it is a National Wilderness Area, it is for the birds! Not for humans.
They nest on the island to get away from humans. Nesting herons and egrets are susceptible to nest abandonment if disturbed in the nest building and early incubation stages of breeding. That is why they tend to nest on secluded islands away from people. Black-crowned Night-Herons are an Ohio state listed species and require certain habitat components to nest successfully. The main requirement is smaller trees less than 20 feet to build their nests.West Sister Island is owned by the U.S. Fish & Wildlife Refuge-Ottawa NWR. The crew that ventured to the island were refuge, Ohio Division of Wildlife, and Observatory personnel. State and Federal Wildlife personnel and Mark Shieldcastle, BSBO Research Director conducted nest surveys and the Observatory along with refuge interns conducted the banding of the nesting colonial birds.
We were almost two weeks later than we wanted to be first getting to the island, so the chicks were big chicks. Here are the beautiful looking Black-crowned Night-Heron chicks when they are a few days old:And here they are when they are a week to 10 days old:They do not like nest invaders so they make themselves look big and scary! It did not deter us mighty banders. They look scary but have fleshy beaks so not so painful as a cormorant or egret.Here is how we got to the nests with a ladder which John Sawvel the ladder man carried and manuevered among the trees for us to band 87 birds this day. Here is John and Debbie the refuge intern at a Night-Heron nest.Ken Keffer, BSBO Education Director was my second bander for the day. He is holding a Great Egret chick to be put back in the nest tree.Small white chicks of Snowy Egrets and Cattle Egrets and occasionally Little Blue Herons all nest on the island and look very similar. Here is Kyle, a Youth Conservation Corps student with a Cattle Egret chick.They all look pretty clean but this is not a clean job nor does it smell like roses on the island either. The chicks method of deterring predators is to either show us what they had for lunch or show us the recycled version. When you are fed fish and crayfish, what is it going to look and smell like? Roses of course! Here is what happened while I was talking on the radio to the refuge manager Doug Brewer. I guess this bird told us what he thought of us! It is an island paradise for the birds. The island holds 40% of all the nesting herons and egrets in the U.S. Great Lakes. It is an important island to these birds and we only disturb them once or twice during the chick season. It is with great thanks to the Ottawa NWR and Ohio Division of Wildlife for sharing the ride to West Sister Island and allowing us to band the herons and egrets. It is truly a cooperative effort to learn about the life history, wading bird ecology, and understand what these birds require on this very important island.