just back to the topic of WW Bl Terns. I came across the page in my field notebook of the Waimakariri river survey I mentioned in an earlier post.
The survey was on 1 Nov 2018.
We found 1 bird in dark dalmation plumage 1 km above the Harewood Crossbank (HCB on the map below). Thats out from the big bump in the road you drive over just past Isaacs on the way to Orana Park - known to all CHCH children as the place where dad's speed up and the car gets airborne!
we found 1 in full BP 3 km above Harewood Crossbank.
And a pair (1 in full BP, 1 in 50% BP 4 km above crossbank at a place where the main channels of the river merged into one big channel for several hundred metres and a colony of 105 B/F Tern and 2 WW bl Terns were strung out along its edge.
Two more birds were found 12 km above Harewood crossbank (1 in full BP, 1 in dalmation plumage).
So a total of 6 birds - 2 pairs and 2 singletons. 3 in full BP, 1 in half BP, 2 in dalmation plumage. We had a big team of surveyors stretched across the riuverbed, all listening in on radios. Everyone was aware of the WW Bl Terns and none of these birds sneaked past and was double counted - so 6 genuine individuals, and all showing Southern Hemisphere moult cycle.
As I said we went down to look for nests/chicks in following weeks, but a big flood washed everything away so tantalising close but no concrete evidence of breeding.

- WW Bl tern map.JPG (208.13 KiB) Viewed 422 times