Grey wagtail experience

Hi all, just joined the community. I have been feeding the birds in my garden since last June. As I haven't completed a full year of bird feeding yet, I still have a lot to learn about what to expect from my feathered visitors and what they expect from me!

I've been very fortunate enough to have daily visits from a female grey wagtail since October. I live close to a river so I expect she will be nesting near it in the spring/summer. She eats from a ground feeding tray under an RSPB cage with the smaller holes.

Does anyone have experience with grey wagtail visits and can give me an idea of what to expect when nesting season begins? Is it likely the wagtail will continue to visit my garden for food? The reason I ask is because if so, I'd like to offer her live mealworm/waxworms if she's interested. And if she would be interested in them I have to devise a way to offer them so that my daily mob of starlings (whom I'm hoping might move on some time soon!) do not gobble everything before my wagtail gets a chance!

I have spent a lot of time and money (as I'm sure many of us do) achieving a balanced set-up so that any birds that visit my garden get a fair chance at a snack. I plan to purchase a Guardian suet pellet/mealworm hanging feeder and put it on the ground for my robin and blue tits to provide them with live mealworms. I believe this will be 'starling proof' unlike my ground feeding cage. I don't think it will be suitable for my wagtail though. Not sure if she'd squeeze through the holes or get her long tail in and out!

Any experience or knowledge you can share with me on what I might expect from my wagtail visitor in the coming months is greatly appreciated!