Gannet colony, Muriwai.

[David Riddell]

My view would be that we're only "directly responsible" for the burgeoning seal numbers in the sense that we've stopped hunting them and have allowed them to recover. The low numbers of seals that have prevailed within living memory are the aberration - we don't know whether there were seals on Oaia Island in pre-human times, but chances are there were. There are plenty of places that gannets can reach which seals can't get to - I don't think they'd get up the cliffs to the mainland colonies at Muriwai for example - so there should be room for both. I'd say just enjoy the seals as an additional feature of Muriwai's natural environment.

[Neil Fitzgerald]

I'm for leaving them to it. I think it's great to see seals slowly recolonising places where humans wiped them out. Are gannets on the island more historic than seals?

[Jim_j]

Yes tricky - let nature (re?) take its course or actively manage.
There has been lots of precedents set - e.g. with weka and as I recall harrier on Tiri for the kokako.
I think if gannets were endangered there would be a case for it but on balance probably not the best use of the conservation dollar.

cheers
jim

[Ian Southey]

Gannet numbers are booming just like the seals. I think there has been a steady increase in numbers of birds and colonies ever since indications of numbers can be gathered. Same reason as the seals. It's a recovery. Pre-European hunting by Maori is probably a more likely reason for the general absence of breeding colonies of Gannets on the mainland. They've had a better run as no one was clubbing them by the thousand to sell their skins in the early European period. I wonder if there are enough seals around even now to go out in a longboat and harvest skins at the rate they used to take them in the early 1800s?

That both are doing well is a good thing and I don't see any need to favour one over the other.

Ian

[zarkov]

I'll go along with the majority opinion, since I suspect the horse has bolted on Oaia anyway. Up until yesterday I thought it was possible for both species to co-exist on the island, but the seals are clearly colonizing the island in great numbers when the weather is bad, and may be breeding there as well. I'd be fascinated to know what is actually going on there instead of surmising from the mainland.

I'm a seal fan too, and there's no doubt the numbers are way up in recent years, with colonies at Takatu, and South head of the Kaipara that I regularly visit in my kayak. Pups are a common sight in the Hauraki Gulf now, however attempts to establish new gannet colonies in the Gulf are meeting with mixed success.

[zarkov]

Among a myriad of gannet photo's I took last week at Muriwai, were several banded birds including this one.

Can anyone tell me the significance of it?

[zarkov]

[youtube]cG0Lqx6JxgQ[/youtube]

Gannet gathering nest materials in 40 knots of wind, last Wednesday.

Also other vids taken the same day on my Youtube channel.

[zarkov]

Oaia Island today. Not surprised to see it's now a seal rookery with pups clearly visible. Gannets have abandoned it..

By comparison, the northern Gannet colony, numbers possibly slightly down, but with a lot of WFTs in the lower right corner of the pic..

Edit: Maybe a little early for a final gannet count.

[zarkov]

Lots of Gannets on Oaia Island this year. I just had my small binos, so couldn't count them, but looks like more than a hundred, with a corresponding slight drop on the mainland. I'd like someone to confirm this if they've been to Muriwai recently. There's been none there for a couple of years, so this is great news.

Unusual spring weather with almost no SW gales this year may explain why the Gannets have started nesting again, since there's been no incentive for the fur seals to disrupt the colony. I'm sure that seal incursions when the birds are nest building would prompt them to abandon the island for the season. Once they've established in numbers and laid eggs, they would probably defend the site. We shall see.