Anyone noticing big influxes of NZ Scaup?

[andrewcrossland]

Hi team, staff from the 3 councils in central
Canterbury have just completed a sub-region wide census of NZ Scaup and there’s about 4000 birds missing. If anyone notices them somewhere please let me know?
The Bromley Oxidation Ponds which usually hold 4000-6000 scaup at this time of year are not currently suitable as a feeding site for scaup (or other water birds) and held only 89 birds. There’s a little under 3000 across Central Canterbury so that’s 4000 plus that have gone further afield.
This has never happened before so it’ll be interesting to see how far they disperse?

[Hypno]

Why is it currently not suitable for feeding ?

[Hypno]

I saw today on a FB community page the lack of birds on the ponds has been raised. poster claims the ponds have zero Birds and is speculating it is to do with the Treatment fire and that it has "destroyed an Avian sanctuary"

[FraserGurney]

Peter Langlands recorded a flock of 1000+ scaup on Lake Forsyth a day or two ago, could be some of the Bromley birds

[andrewcrossland]

It kind of is, we believe those birds do originate at Bromley but 1000-3000 are expected there each winter - it’s part of the usual dispersal. There’s been 800-1000 at lake Forsyth for at least 2 months so the missing thousands are not there.
Cheers

[andrewcrossland]

Hi folks, sorry I wasn't able to reply to Hypnos post of 3 May.

This media story might help explain the situation a little.

https://www.stuff.co.nz/the-press/news/ ... w-very-low

We found the missing Grey Teal (half of them are feeding on Gracilaria weed beds on the adjacent estuary and others have moved to other lowland Central Canterbury wetlands, and we've found the Shoveler - they've moved to other large coastal wetlands. But we're missing thousands of Scaup so I'm hoping they'll show up somewhere soon?!) Please post sightings here of any unsual large flocks from areas beyond the Central Canterbury coastal lowlands and Lake Forsyth.

On the topic of midges, they're the basis of the food chain for many waterbirds on oxidation ponds.

From what we understand as it says in the article the poorer-than-usual quality of wastewater seems to be largely responsible for the temporary disappearance of midges at the Bromley Oxidation Ponds, which as many people know support really impressive populations of native waterbirds.

Ofcourse, there are other factors that can make midge populations drop (such as environmental changes, various types of control programmes, possibly climate and weather factors, etc), and ornithologists out there should not be shy to start conversations with controlling authorities of oxidation ponds around the country if midge numbers become unusually low and waterbird numbers drop. There needs to be a balance, doesn't there, between midges reaching levels of abundance where they cause an unacceptable nuisance to neighbouring communities and where reduction in abundance has unintended consequences for indigenous biodiversity.

With the historic loss of so many coastal wetlands in NZ, its been the oxidation ponds that have taken on the burden of supporting tens of thousands of indigeous waterbirds nationally through critical stages of their annual cycles - particularly during the moult and post-breeding flocking phases, but also for over-wintering populations in some areas and in the case of NZ Scaup and Dabchick as no doubt nationally important breeding sites. If these sites lose their midges the birds will potentially lose their food.

cheers

[Adam C]

I'd say a good balance of midges (or more importantly their larva the bloodworms) is probably the most important topic as an absolutely essential base of the food chain we can have a discussion about. Arctic migrants and staging/wintering native waders rely on them at Ellesmere and coastal lakes and the oxidation ponds are of zero interest to birds without them. The midge should almost be regarded as a national bloody treasure in terms of importance to the food chain of wetland wildlife.

[andrewcrossland]

Yes I agree. Folks up in Auckland might have their own take on the following story in relation to perceptions of net environmental benefits……,,

https://ourauckland.aucklandcouncil.gov ... blem-gone/