Tuesday, October 20, 2015

List! How to set realistic bird list targets

Few more birders than usual should be stalking Tyto and other hotspots around Ingham over the coming weekend with shire-organised twitching days and nights.

So, how many birds should visitors expect if shire boasts of 240-plus species in Tyto Wetlands and many more in the wider district?

Give up? Don't care? Haven't a clue?

Here's a clue. Go to atlassing site such as ebirdEremaea, select hotspots, open, say, Tyto Wetlands, select last seen to gain chronological list. Now scroll down list, going back in time. Back three months, six months,a year, three years. At any point in time you get a count of species.

Taking a three-year back limit - because ebird listing really took off about then - you'll get 216 species for Tyto. For the top Australian hotspots: Townsville Town Common, 271 listed, 242 in past 3yrs; Werribee Treatment Ponds 263, 227; Cairns Foreshore 259, 194.

Big differences between totals and three years. But even three years is a long time. And many sites show very strong seasonality among species. So last  three months may be closer to reality. For Tyto that would mean about 160 species. The common and Werribee fall behind, to about 135 each, and Cairns drops to 100. Tyto loses fewer birds because it has water year-round (unlike Townsville) and is not so coastal and seasonal as Cairns and Werribee.

I expect for a full mornng to list between 70 and 80 species in Tyto. Add about 30 over a week and another 30 over a month. So, if lucky, 130-140 of the target 160. Which is a long way off the 246 on the printed Tyto list, but it's a realistic figure.

Go to it, visitors. But set sensible targets wherever you bird.

All pictures from recent Tyto outings: Pelican, Shining Bronze Cuckoo, Pied Imperial Pigeon, Yellow-billed Spoonbill, Yellow Oriole, Little Friarbird

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