Aug 10 - Metrics Update

We've looked at the year by county - and we'll come back to that. But, we now have enough data on the year (2023) to compare to the previous 5 years (2018-2022).

Start with the record count by year:

2018: 19,741
2019: 32,694
2020: 20,621
2021: 26,695
2022: 35,517

This is an average of > 27,000/year. We are momentarily at > 27,000 for 2023. So, good!

When looking at things by percent change, numbers can be crazy - best example this year is the Four-spotted Skimmer with 248 observations in 2023 with a single record in the previous 5 years. So I'm limiting the over/under metrics to only those species that have more than 100 observations over the last 5 years. That would be 89 species common enough to be seen routinely.

OVER

First, which species are over - those already considerably above the 5 yr ave (+33%). This is in order of percent over. Bluets are doing well, 6 of the 24. Then Clubtails with 5. Note that these Bluet species are not among our our most common, while the Clubtail species are our most common. Just more looking? Overall Bluet numbers are similar to past years, with the big numbers still to come for Familiar Bluet and Orange Bluet. Clubtail numbers, as a whole, are nearly double the average, so a good year for Clubtails.

Vesper Bluet
Ashy Clubtail
Pronghorn Clubtail
Aurora Damsel
Blue Corporal
Turquoise Bluet
Rainbow Bluet
Lancet Clubtail
Westfall's Slender Bluet
Spot-winged Glider
Common Baskettail
Unicorn Clubtail
Spatterdock Darner
Midland Clubtail
Eastern Least Clubtail
Dot-tailed Whiteface
Spangled Skimmer
Stream Bluet
Cyrano Darner
Elegant Spreadwing
Eastern Red Damsel
Skimming Bluet
Sweetflag Spreadwing
Prince Baskettail

UNDER

Next, species that are under, with 2023 count less than half 5 yr ave - many of these are autumn species, so there's a likelihood of increase. Note that Great Blue Skimmer and Carolina Saddlebags have big declines (2023) from previous years.

Spotted Spreadwing
Shadow Darner
Great Spreadwing
Arrow Clubtail
Green-striped Darner
Russet-tipped Clubtail
Blue-faced Meadowhawk
Great Blue Skimmer
White-faced Meadowhawk
Plains Clubtail
Band-winged Meadowhawk
Carolina Saddlebags
Fawn Darner
Citrine Forktail
Wandering Glider

UNSEEN

Here we go - these are the species documented in the last 5 years with no 2023 data (yet) - in order of survey years count. Again, several of these should turn up. Note the season is likely over for Common Sanddragon, Belted Whiteface, Hagen's Bluet, Riffle Snaketail, Frosted Whiteface, Marsh Bluet, and American Emerald. Our 2023 species count is at 131. The 5 year average is 138, we'll need 7 from this list to meet the average. Other than the first 5, these occur in very limited numbers - either quite rare or only occasionally arrive on the wind.

Smoky Rubyspot
Common Sanddragon
Lance-tipped Darner
Belted Whiteface
Laura's Clubtail
Golden-winged Skimmer
Striped Saddlebags
Hagen's Bluet
Riffle Snaketail
Ocellated Darner
Duckweed Firetail
Rambur's Forktail
Frosted Whiteface
Marsh Bluet
American Emerald
Little Blue Dragonlet
Smoky Shadowdragon
Cherry-faced Meadowhawk
Brush-tipped Emerald
Scarlet Skimmer
Band-winged Dragonlet
Furtive Forktail
Skillet Clubtail
Saffron-winged Meadowhawk

MISSING

Finally, species with historical records but with no records in previous 5 years - in order of historical count. It's good to look at this every now and then. This is in the order of historical numbers. Some of these were vagrant when observed, some were here and are now gone.

Canada Darner
Mottled Darner
Wabash River Cruiser
Hine's Emerald
Plains Emerald
Allegheny River Cruiser
Riverine Clubtail
Northern Pygmy Clubtail
Umber Shadowdragon
Taiga Bluet
Appalachian Jewelwing
Taper-tailed Darner
Spine-crowned Clubtail
Georgia River Cruiser
Variable Darner
Kennedy's Emerald
Incurvate Emerald
Atlantic Bluet

Posted on 10 de agosto de 2023, 01:34 PM by jimlem jimlem

Comentários

Valuable analysis and very interesting. Eliminating the rare/non-common species from the analysis is a very good idea. Using 5-year average values to compare to current 2023 specie values seem reasonable, especially since the 5-year average observation total roughly equals the current year total observations. If these two values deviate significantly, one might want to apply some sort of normalization process to the species analysis.

Very good that the number of "Over" species outnumber the "Under" species.

Unfortunate that the Unseen list is so long, but as you say, the season is not over yet and we only need 7 species to meet the average.

Wonder if the Missing list species are observed anywhere else. Can they be re-populated to Ohio?

Publicado por mikeabel 8 meses antes

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