Wednesday, 29 April 2015


I haven't had much time for birding lately, but I usually manage to find time for my morning walk.  This morning, I saw a new species for my walk lists.  It was a Collared Sparrowhawk, not something you see every day in the suburbs.

I don't have a photo of a Collared Sparrowhawk, so here's a picture of me learning how to band a bird, taken a couple of weeks ago by Dena Paris, the girl who was teaching me.

I was delighted to add a new species to my walk list this morning, on the last day of April.  The last new species I saw was, strangely enough, on the last day of March.  It was an Eastern Spinebill.  I began to wonder how many more new birds I might see.

There are, I am told, many formulae for estimating the total number of bird species in a patch.  One devised by Chao goes like this:  the total number of species is equal to the number that you've seen, plus the number of species you've seen once, squared, divided by double the number that you've seen twice.

I've seen a total of 34 species on my morning walks, just five of them only once.  These are Black-faced Cuckoo-Shrike, Australian White Ibis, White-plumed Honeyeater and the aforementioned spinebill and sparrowhawk.  I've also seen five species twice:  Silver Gull, Musk Lorikeet, Australian Raven, Masked Lapwing and Pacific Black Duck.  So, according to Chao, the total number of species here should be:  34 + (5 x 5) / (2 x 5) = 34 + 25/10 = 34 + 2.5 = 36.5.  Now I'm looking forward to seeing those extra 2.5 species!  It will be fascinating to see how long it takes me.