Tuesday, May 31, 2016

"THE RED-NECKED GREBE (PODICEPS GRISEGENA): A PORTRAIT" - ARTICLE BY SANDRA HAWKINS



Sandra is a local photographer, naturalist and an active member of the Friends of Sam Smith Park steering committee.

As of the posting of this article, there are seven grebe pairs in the bay sitting on eggs - six on provided platforms and one on a rock outcrop.
 
“In order to see birds, it is necessary to become part of the silence”.   Robert Lynd

by © Sandra C. Hawkins*

The winter Olympic Games are long over, and soon it will be time for those of the summer to begin. Although the “human” games happen every four years, I think in terms of a different sort of Olympiad—the one that unfolds with each successful return migration and nesting cycle.
Surviving on the wintering grounds, completing the long flight northward, seeking a mate, locating and defending a nesting territory, building a nest, mating, laying eggs, protecting, feeding and raising the young--all in such a short period of time, are truly feats of Olympian
PAIR BONDING
proportion. Human athletes train for a scant number of years. Birds train for their entire lives.
In spring, soon after the ice recedes from Ontario’s lakes and ponds, the plaintive wail of the Red-necked Grebe shatters the winter’s silence. For the past few years, however, the shoreline of Lake Ontario in the GTA and the marina at Colonel Samuel Smith Park have served as wintering locations for some of these magnificent birds. Although its sound may not be as musical or as lilting as that of the White-throated or Song Sparrow, it announces that a new season has begun with grand changes in the offing.

Description, Distribution and Range
Shedding their subtle gray feathers of winter, the Red-necked Grebes that return to Ontario in March are clad in avian finery. With their chestnut necks, distinctive large white cheek patches, natty jet black crowns, dark gray head and long black bills that are yellow at the base, the birds are a sight to behold. They are a medium-sized grebe with a length of 43-56cm, a wingspan of 61-88cm with weight averaging 800-1600g. The sexes are similar in colouration, although the male tends to be larger than the female.
Although Red-necked Grebes are listed as one of the most common diving birds found on large numbers of lakes in western Canada, their presence in our area has most often been associated with migration alone. The Canadian Atlas of Bird Banding describes their breeding range in Ontario to be “from Lake Superior westward...” Such statistical data will most certainly need updating thanks to our resident wintering and breeding population in Colonel Sam Park. It is hoped that the park’s recent designation as an Environmentally Significant Area (ESA) will provide the Grebes with added protection.  

Courtship
Red-necked Grebes commonly form breeding pairs while still on the wintering grounds and they tend to be monogamous during the breeding season that lasts from May to
COURTSHIP "GIFTS"
September. Sexual maturity occurs at 1-2 years.
The courtship period is noisy and active and may become highly aggressive, especially when other Red-Necked Grebes dare venture too near. Although the birds tend to be largely silent during the non-breeding period, such is not the case when pair bonds are being established. Whether singly or as part of a duet, the birds commonly enter into bouts of loud wailing during their highly ritualized courtship and territorial defence displays.  At times they appear to run on the surface of the water as they rush closer together in an upright position and present each other with “gifts” of green vegetation. Thrashing of wings, hunching of bodies and pointing of bills upward are parts of the “arsenal” employed when interlopers begin to encroach.

Habitat and Nesting
In spring, Red-necked Grebes seek out marshy ponds and shallow bodies of fresh water. Although the male initiates site selection, both birds are involved with nest building. Aquatic (emergent) vegetation forms the primary building material for nests that, in the wild, are built atop a “platform” of floating plant material.  Nests are often secured to vegetation at the bottom of a pond. (FOSS offers a very special thank you to Mr. Joe Calico in appreciation for successfully designing and building platforms for the Red-necked Grebes that nest in the Colonel Sam Smith Marina). The upper layer of the nest consists of sticks and bulrushes. It is not uncommon to observe a nest entirely surrounded by open water.
DEFENDING THE NEST
A clutch of 1-9 light blue eggs is laid in a depression formed in the middle of the nesting mound. Both parents share incubation duties lasting 21-33 days. Immediately upon hatching (asynchronous), the downy and precocial chicks climb onto a parent’s back where they will spend most of the next 10-17 days. At times, the brood may be split between the parents in order to spread the demand for feeding equally between the adult birds.
The parents continue to feed the young for approximately 50 days. Fledging occurs after
TURNING THE EGGS
50-70 days. Normally Red-necked Grebes raise a single brood, although re-nesting after a clutch has been lost or the incubation of a second clutch is not uncommon.

Diet
The grebe’s diet is varied and includes small fish, minnows, sculpins, crustaceans, tadpoles, aquatic insects, crayfish and some vegetation. They are also known to catch low flying insects out of the air.
Adult Red-necked Grebes ingest large amounts of their own feathers, while feathers of parent birds are found in the stomachs of
FEEDING THE CHICKS
their small chicks.  It is speculated that these wads of feathers act as a sort of padding that protects their stomachs from sharp fish bones. They may also retard the digestion process allowing bones to dissolve and not pass into the intestine.

Threats and Status in Ontario
Red-necked Grebe populations are relatively healthy and stable in Ontario. They suffer predation from foxes, raccoons, mink, muskrat, pike, Bald Eagles, gulls, ravens, crows and even American Coots. They are susceptible to disturbance from farming, fracking, road building and general human interference with the wetlands and lakes they require for feeding and nesting. Contaminants such as heavy metals and organochlorines that accumulate in the tissues of their prey are suspected for causing thinning of egg shells
RED NECKED GREBE FAMILY PORTRAIT
and egg sterility. Boat traffic near nesting areas should be minimized to prevent disturbance to the birds and their nests.

Conclusion
One of the first books I truly called my own was Ernest Thompson Seton’s “Wild Animals I Have Known”. I treasured my old dog-eared copy and, to this day, have not forgotten the wonderful word portraits he painted. His tales are etched in my mind as though it were yesterday. For those who have not yet read this classic book, I urge you to do so as it recalls memories of a less degraded and threatened natural world. This “portrait” of the Red-necked Grebe is dedicated to such memories.

Resources
http://www.birdsontario.org/atlas/atlasbook.jsp?pg=043 Red-necked Grebes—Atlas of Breeding Birds of Ontario
http://www.ofnc.ca/birding/bbanestdates.html Migration and Nesting Dates for Ontario Bird Species
https://www.allaboutbirds.org/guide/Red-necked_Grebe/id The Cornell Lab of Ornithology—All About Birds
http://www.ec.gc.ca/aobc-cabb/index.aspx?lang=en&nav=bird_oiseaux&aou=2 Canadian Atlas of Bird Banding-Environment Canada
http://www.gutenberg.org/files/3031/3031-h/3031-h.htm (Project Gutenberg free downloadable copy of Wild Animals I Have Known by Ernest Thompson Seton).
Erlich, Paul R., Dobkin, David S. and Wheye, Darryl, 1988, The Birder’s Handbook: A Field Guide to the Natural History of North American Birds, Simon and Schuster, New York, N.Y.
Godfrey, W. Earl, 1990 Rev. ed., The Birds of Canada, National Museum of Natural Sciences, National Museums of Canada, Ottawa.

*This article was first published in Nature Alberta Magazine in 2014. It has been edited to include Ontario references. All photographs were taken at Colonel Samuel Smith Park or at Humber Bay East Park.

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