|Dragonfly, a helpful insect predator|
Birds are one of the most helpful animals in my garden. They eat all sorts of pests: from slugs and snails, to aphids and woodlice. I have two mature trees at the edge of my garden, plus many different small trees, shrubs, and plants of various heights, to provide both cover and nesting sites for all kinds of local birds. They drink and bathe in the shallow end of our pond. I even have some plants and shrubs which I keep specifically with birds in mind, like guelder rose and berberis, both of which have lots of berries and provide good hiding places and shelter.
Of course, there is a small downside to having birds: they can eat my food before I get a chance to! However, for the most part, I have found having such a diverse amount of living bird food (both plant/seed/berry and insect), means the birds aren't much interested in my fruit and vegetables. I keep my soft fruit bushes surrounded by other plants in a polyculture, and the birds don't seem to notice the berries. However, I net my small morello cherry tree against birds, as those bright red cherries are simply irresistible; I don't blame them for wanting to eat them all! And after I have picked around 75% of them, I remove the net and let the birds have the rest.
This year we've had regular visits from many different birds: goldfinches, robins, wrens, sparrows, blackbirds, thrushes, and doves. The blackbirds and thrushes are particularly good for controlling pests, and I love to see them out and about teaching their children how to hunt bugs and slugs.
Frogs and toads
We dug our pond in 2014 to attract frogs and toads, first and foremost; since then, we have seen one or two, hopping about the garden. These gentle amphibians are great slug eaters, and I hope they build up a good population in our pond, which has a shallow end for getting in and out, and is deep enough for frogs and toads to hide at the bottom without being seen.
One of the cutest local predators are the spiky hedgehogs. I have not seen any yet this year, but in past years have spotted them both in my garden and in the neighborhood. I have plenty of low growing ground cover plants around the edges of my garden, as well as brush piles and loose leaf litter--all great places for them to sleep or hide. I also have two or three small gaps in my fences to allow them to get into and out of the garden, as they like to range far and wide in their hunt for slugs and snails.
Lots of bugs are an asset in the garden. Many, like ladybugs and hoverflies, are well known aphid-eaters. To attract and foster them I actually leave the aphids alone, and simply let these predators handle it. Since my garden is so diverse in plants and weeds, I have built up a regular population of these helpful predators over the years; I really don't have much of a problem with aphids any more. I've often seen sparrows delicately eating aphids, too.
Other bugs, like bees and butterflies, are needed to pollinate flowers for producing fruit. I have many flowers in my garden, and try to have something flowering at all times during the year--even in the middle of winter. I want bees in my garden at all times, to help pollinate my fruit trees, and vegetables like zuccini and tomatoes, and to help me in my seed saving adventures.
There are more helpful creepy crawlies: beetles to eat slug eggs, wasps to eat cabbage white moths and caterpillars, spiders to eat flies, dragonflies to eat mosquitoes, and so on. All of these little creatures are welcome in my garden, and the abundance of plants and weeds means they have plenty of habitat.
All these creatures act together, along with their plant and micro-organism counterparts, to add to the health and vitality to the ecosystem. Each creature provides a function, and some--like the pollinators--are absolutely necessary for my garden to grow and thrive. Because of this, I operate on a live and let live policy, even for pests* and weeds: they all have a role to play; and my garden, and little part of the world, is more vibrant and productive for it.
*Disclaimer: I will kill slugs, snails, and cabbage white caterpillars on sight, but I only step on the ones I see; I don't put down slug killer/insecticide. Every other pest gets a free pass--and they generally don't last long enough to become a problem.