If you really want to help out the local native wildlife the I suggest you try and stick with the endemic species in your area.Your council will most likely have a list of species that occur locally.
While I agree with the sentiments behind this statement, it is not always the best option in a suburban garden. There is also a lot more consideration gone into my suggestions than what I have have indicated. Allow me to explain.
With plants that produce nectar to attract birds and insects, local species and varieties will often (though not always) have limited flowering periods. It is the combination of many different species, which flower at different times, that provides continuity of food supply in nature. Many species are also sparse flowering or may produce only little nectar, overcome in nature by the wide foraging of birds and insects. By growing plants that have quite an extended flowering period and are known to produce copious amount of nectar, you give yourself more opportunity to attract birds and insects to your garden throughout the year. At the same time, you want to provide food sources similar to what the local wildlife is used to. All the species (not the hybrids) I have suggested, bar
Callistemon viminalis (Captain Cook cultivar) are found in the Lake Macquarie region. (C. viminalis occurs from Grafton north.) this also helps ensure that the climate and soils are suitable. All bottlebrushes produce similar style flowers and nectar, so substituting one for another is not usually an issue. Wattles, for example, are also great plants for attracting insects in particular, even when out of flower. And many birds eat the seeds. However, birds also distribute some undigested seeds in their droppings, so I have deliberately avoiding suggesting them so that varieties and species not local to the area don't get into any local bushland which might be in the vicinity. It can often be difficult to source true local plant material in areas which do not have a group dedicated to growing local natives. Where true local wattles and similar suitable seed producing natives, can be obtained, then go for it.
The structure of plants chosen for attracting native birds to gardens is also important. Plants in gardens are much out in the open than those in most local bush and scrub. This can make many of the smaller species of birds in particular more vulnerable to predators such as cats and butcher birds. To offset this, it is wise to choose full, bushy plants that also have lots of flowers within the body of the plant, which affords much more protection to foraging birds. This is particular important in this case where the intended plants will be shrubs (around 2m high), not trees, and will be planted in the open.
There is a bit more to it than meets the eye...
Blue