Linnets on the Sea Cabbage

[Wild-Woman]

Back in the summer, we visited Cuckmere Haven- one of my favourite areas in the south.
On the shingle before the beach dips down, there are some pretty amazing plants and scarce habitat, consisting of Vipers Bugloss, Horned Poppy and a huge amount of Sea Cabbage.
On the cabbage there were Linnets. We couldn't find what was attracting them there. Any ideas?

[thebeard]

gardeners often have to protect their brassicas from birds - i think they eat the young shoots and flowers - this is probably why the linnets were there.

[Dogghound]

Yes Linnets often feed on the seed heads even when they are unripe. They also feed these to their young. Linnets like brassicas such as oil-seed rape so I can see why sea cabbage is appealing to them.

[Jim Ford]

Surely it's Sea _Kale_ (Crambe maritima)?

Crambe maritima - Wikipedia, the free encyclopedia

I gathered some ripe see capsules a few weeks ago. They have a thick hard shell - I'd estimate 1mm thick. I'm surprised linnets can crack them! In in spite of the shell they're very light. I guess - like coconuts - they're 'designed' to float long distances without the seed inside being damaged.

Jim

[Dogghound]

Originally Posted by Jim Ford

They have a thick hard shell - I'd estimate 1mm thick. I'm surprised linnets can crack them! In in spite of the shell they're very light. I guess - like coconuts - they're 'designed' to float long distances without the seed inside being damaged.

May be one of the reasons that they often feed on unripe seeds, which are softer.

[Gill Catton]

Or it could be that they were searching for invertebrates for their chicks?

[healfdan]

Originally Posted by Gill Catton

Or it could be that they were searching for invertebrates for their chicks?

I agree with Gill, invertebrates especially aphids and caterpillars of the small and large white butterfly thrive on Sea kale. This year, along the West Sussex coast, there has been an abundance of small whites

[Dogghound]

Probably a bit of both however nestling Caudueline finches are predominantly fed on seeds. We tend to get far greater breeding success of linnets when lots of oil seed rape is present in the area. Chick survival is much higher than years when rotation crop like sugar beet etc is planted. Insects tend to form a very small part of the linnet diet even when feeding nestlings.

[Wild-Woman]

Originally Posted by Jim Ford

Surely it's Sea _Kale_ (Crambe maritima)?

Crambe maritima - Wikipedia, the free encyclopedia

I gathered some ripe see capsules a few weeks ago. They have a thick hard shell - I'd estimate 1mm thick. I'm surprised linnets can crack them! In in spite of the shell they're very light. I guess - like coconuts - they're 'designed' to float long distances without the seed inside being damaged.

Jim

Yes it Sea Kale but it's one of those plants that some people refer to as cabbage. I'm one of those!

[Wild-Woman]

Originally Posted by Gill Catton

Or it could be that they were searching for invertebrates for their chicks?

We looked hard, thinking aphids or caterpillars but couldn't find any. I suppose the insects that would be there must be salt tolerant and used to being blasted by the wind daily.