Brown patches on my lawn

This does sound like Chafer grub (at this time of year) or early Leatherjacket grubs. I would suggest you have a look under some of the brown turf and if you can see any grubs (White for Chafer and grey-brown for Leatherjackets), then you know you have them.

There are nematodes that can be applied to the lawn to kill these pests but the grubs must be present. I do not think it is Vine weevil, as they do not normally attack lawns. I suspect it is Chafer grub and the birds are being attracted to them. They then rip the lawn up looking for them. Try using Chafer Grub Killing nematodes if this is the cause.

Hope this helps.

Regards Julian