Cormorant Menace?

I just sent the following email to the most excellent IslandWalk Lakes Committee.

When I posted my 2021-2022 IslandWalk Birds report, I noted a lot more double-crested cormorants than what I remembered as being usual.

A month or so ago, I read an article about how 10s of 1000s of cormorants were wreaking havoc on the salmon population in the pacific northwest. I couldn't find that article again, but if you google DuckDuckGo "cormorant problems", there are dozens of articles.

Then a couple of weeks ago, my wife & I vacationed in Ottawa, Canada. On the way there we spent a night in Clayton, NY, and took a 5 hour boat tour of the Thousand Islands - the area where the St. Lawrence River leaves Lake Ontario.

We learned an island is defined as: 1) above a minimum size; 2) always above water; 3) has at least 1 tree. We were shown 1 ~30-40' island that had no tree, but instead dozens of cormorants. The cormorants had started roosting there, and their acidic droppings had killed all the trees on the island.

I wanted to get at least 1 more data point, so I compiled my 2020-2021 IslandWalk bird data:

http://portraitofthedumbass.blogspot.com/2022/08/islandwalk-birds-2020-2021-season.html

Between the 2 sets of data, there was indeed a large increase in cormorant #s. 2020-2021, I counted at least 1 cormorant 100% of the time, the average was 3.2 birds, with a max of 10. 2021-2022, it was 95% of the time, but the average was 7.9, with a max of 25. That is around a 2.5x increase.

Hopefully I will be counting again this year, and hopefully this trend will not continue. And, of course, 2 data points is not nearly enough from which to extract a trend line.

But I wanted to bring it to your attention as something that needs to be watched. Does our lake management company also monitor the wildlife? If so, maybe pass this on to them? Maybe this is something that could be nipped in the bud before it becomes a problem?

It's too bad, I have enjoyed watching the cormorants fish on Lake #1, and I like how an aid to identifying them is how they always, whether swimming, standing on the bank, or roosting in a tree, keep their head at the same 20 degree angle.

And, of course, cormorants are protected by the Migratory Bird Treaty.

Best regards,
Chris Heinz

IslandWalk Birds, 2020-2021 Season

My overall birdwatching strategy for IslandWalk is posted here.

My 1st ever "IW state of the birds" post was for the 2021-2022 season. I am cloning this post from that post. That post contains discussions of things I found interesting about a lot of the species.

I was of 2 minds about posting the data from 2020-2021. There were only 9 X & X2 datasets, and the final X dataset, on March 4, 2021, was cut short when the arch of my right foot totally gave out at the 4.5 mile point in the 5.41 mile walk. I went straight home (cut down Freeport rather than walking the SW corner) and finished at 5.0. But, there is a bird issue, and I wanted this data for comparison purposes, so I went on and entered it.

[Note, I have quit going barefoot on our tile floors, and have put arch supports in all my shoes & my new comfy slippers, and my feet are doing much better. :-) Hopefully I will be up to walking the 5.41 & 5.47 mile X & X2 routes by December.]

I will do a follow-up post on the bird issue I mentioned. (Hint: cormorants).

I manually entered this data in this spreadsheet

I will be reporting for all observed species the following 4 datapoints:

1. % of days seen;
2. total birds counted;
3. average;
4. max.

Note, the 2021-2022 post, I reported "# of days seen" vs "% of days seen". I will go back to that post and revise it to show the % instead of the #, for easier year to year comparison.

Doing this post ~18 months after the fact, I don't remember any fun anecdotes to share.

Here's the link to the IslandWalk hotspot at eBird.org.

Each bird name listed below is linked to its IslandWalk activity page in eBird.org. So click on the name, you will get a picture & all the data eBird has on that bird in IslandWalk.

Swimmers

I guess all are dabbling "ducks"? "Dabbling" === "stick your bill down in the water & swish it around & eat what you get from that" - as opposed to diving ducks.

• mottled duck: % days 100; tot 293; avg 33; max 51.
• muscovy duck: % days 100; tot 186; avg 21; max 41.
• common gallinule: % days 56; tot 9; avg 1.8; max 3.

Divers

• pie-billed grebe: % days 100; tot 53; avg 5.9; max 13.
• hooded merganser: % days 56; tot 20; avg 4.0; max 10.
• lesser scaup: % days 56; tot 20; avg 4.0; max 6.
• ring-necked duck: % days 56; tot 21; avg 4.2; max 6.
• double-crested cormorant: % days 100; tot 29; avg 3.2; max 10.
• anhinga: % days 100; tot 54; avg 6.0; max 10.
• brown pelican: % days 56; tot 9; avg 1.8; max 5.
• belted kingfisher: % days 0.

Waders

• great egret: % days 100; tot 42; avg 4.7; max 6.
• great blue heron: % days 44; tot 4; avg 1.0; max 1.
• snowy egret: % days 89; tot 14; avg 1.8; max 3.
• cattle egret: % days 11; tot 1; avg 1.0; max 1.
• tricolored heron: % days 100; tot 36; avg 4.0; max 7.
• little blue heron: % days 33; tot 3; avg 1.0; max 1.
• green heron: % days 0.
• wood stork: % days 44; tot 4; avg 1.0; max 1.
• white ibis: % days 100; tot 166; avg 18.4; max 41.
• glossy ibis: % days 78; tot 51; avg 7.3; max 14.
• limpkin: % days 0.

Beach Birds

• killdeer: % days 11; tot 1; avg 1.0; max 1.
• black skimmer: % days 0.

Raptors

• osprey: % days 67; tot 8; avg 1.3; max 2.
• bald eagle: % days 0.
• cooper's hawk: % days 0.
• red-shouldered hawk: % days 0.
• broad-winged hawk: % days 0.
• swallow-tailed kite: % days 0.
• loggerhead shrike: % days 22; tot 5; avg 2.5; max 4.
• black vulture: % days 11; tot 2; avg 2.0; max 2.
• turkey vulture: % days 78; tot 14; avg 2.0; max 4.

Corvids

• fish crow: % days 67; tot 132; avg 22.0; max 55.
• blue jay: % days 67; tot 40; avg 6.7; max 20.

Perching Birds (Passerines)

• mourning dove: % days 100; tot 32; avg 3.6; max 8.
• eurasian collared dove: % days 22; tot 3; avg 1.5; max 2.
• common ground dove: % days 0.
• common grackle: % days 100; tot 77; avg 8.6; max 61.
• boat-tailed grackle: % days 11; tot 1; avg 1.0; max 1.
• red-winged blackbird: % days 0.
• european starling: % days 0.
• northern mockingbird: % days 89; tot 65; avg 8.1; max 42.
• brown thrasher: % days 0.
• northern cardinal: % days 0.
• red-bellied woodpecker: % days 78, tot 44, avg 6.3, max 15.
• pileated woodpecker: % days 0.
• downy woodpecker: % days 0.
• northern flicker: % days 0.
• palm warbler: % days 100; tot 85; avg 9.4; max 20.
• black-and-white warbler: % days 0.
• yellow-throated warbler: % days 0.
• prairie warbler: % days 0.
• blue-gray gnatcatcher: % days 22; tot 3; avg 1.5; max 2.