Goldfinch with conjunctivitis
Goldfinch with conjunctivitis
The term “potluck” refers to a meal or a party to which each guest contributes a dish. A second definition mentions “a situation in which one must take a chance that whatever is available will prove good or acceptable.” Frequently my bird column falls into that second category as I encounter or photograph random birds and then attempt to turn them into subjects of good and acceptable reader interest.

So this week’s offerings are strictly potluck. Let’s visit some totally unrelated species or subjects with no apparent linkages. My first menu offering is an immature Black-crowned Night-Heron found at Thomaston Harbor, where they are perennial summer nesters. The species’ namesake black crown takes a couple of years to acquire. Night-herons are fairly common in Maine but are secretive creatures that nest amidst thick protective cover located near water. To minimize competition with other heron species, they are most active after dark while patrolling marshes, streams and tidal flats. They are not fussy eaters in the least, consuming anything from earthworms to crayfish, mussels, amphibians, snakes, rodents, birds and eggs. Night-herons can also raise havoc with seabird nestlings at coastal breeding colonies.

Next, join me on an August boat trip to Seal Island near Vinalhaven to witness Wilson’s Storm Petrels wheeling and darting above the wave tops. Members of an order of seabirds known as tubenoses, petrels have tubular nostrils that may serve to enhance their sense of smell or to keep salty bill excretions away from face and eyes. Petrels are light and airy in flight as they glide and hover buoyantly with feet pattering the water to snatch up tiny organisms. Appearing inky black at a distance, dozens of petrels zipped around our boat, revealing their broad white tailband.

Slightly smaller than a starling, these amazing flyers alternate seasonally between the ocean’s poles. These petrels arrive in the North Atlantic region by mid-May but actually nest on islands and cliffs of Antarctica and southern South America from November to May. During Maine summers, they are perhaps the most numerous seabirds off the U.S. Atlantic Coast. These deep-ocean dwellers are occasionally seen from shore during strong winds. A similar petrel, the Leach’s Storm-Petrel, nests on Maine’s coastal islands each summer.

Finally, I’m sharing a photo of a goldfinch with serious eye problems, namely conjunctivitis. Some history: When House Finches were smuggled from the West Coast in the 1940s to be marketed by the pet trade as “Hollywood Finches,” some members of the population carried the parasitic bacterium Mycoplasma gallisepticum, more commonly found in domestic chickens and turkeys. When eventually released into the wild, this small core of finches infected other species, including American Goldfinches, Evening Grosbeaks and Purple Finches.

Occasionally you may notice birds with red swollen or runny eyes at your feeders. Infected individuals appear unusually tame or unwary. They may be partially blind in one or both eyes, allowing one to approach them or even hand-capture them in some cases. While some birds may recover, many die of starvation, exposure or predation.

Best practices to minimize potential infections are cleaning of feeders and bird baths on a regular basis with a 10-percent bleach solution. Avoid using old or musty seed and rake ground areas in summer to remove accumulated seed waste. During winter, shovel fresh snow over the areas. Keep platform feeders clean and put out the amount of seed birds can consume within a day or two.