If you don't have a moth trap how about trying your hand at 'sugaring'. This was a popular technique used by lepidopterists before the advent of light traps and is still used to a lesser extent today as it is better at attracting certain species  that are not strongly attracted to light.  Sugaring involves brewing up a sticky treacly concoction which you paint onto several tree trunks/fence posts in vertical strips.

As night falls and you return to the first of the painted strips you should see some moths (amongst other creepy crawlies) feeding at the sugary mixture. Take care if you are using torch with a white light because shining this on to the strip may make some of the moths drop to the floor. A red light (such as the backlight from a bike) is supposed to be better to view the moths as they are not sensitive to the red light. Don't restrict yourself to putting the 'sugar' on tree trunks, try flicking drops onto shrubs with broad leaves. The 'sugar' mixture can be quite damaging to any lichens on tree-trunks so you may want to avoid painting on tree-trunks that have lichens on them.

Here's the recipe I use;

• A bottle of Guinness or other good stout (approx half pint or 250ml)
• One over-ripe banana
• One ripe mango, with the flesh stripped of the stone (optional)
• 2-4 dessert spoons of black molasses or treacle
• 1lb (450g) of the stickiest/darkest sugar you can find

The mixture needs to be heated and the saucepan used should be at least twice the volume of the ingredients, as the mixture is prone to froth up when it is boiled. Mash or liquidise the banana (including the skin) and the mango flesh. Place the banana, stout, molasses, sugar and mango flesh in the large pan. Heat very gently, stirring frequently for 15 to 20 minutes until all the ingredients have dissolved and the mixture is starting to come to boil.  Simmer for 10 minutes stirring occasionally, making sure that the mixture does not solidify at the edges or overflow, until it thickens slightly. Allow to cool, again stirring occasionally. Bottle while still lukewarm. Before use stir in a little spirit (eg rum). Apply with a paintbrush. Have plenty of wet-wipes handy to clean up any sticky hands.

There are numerous variants on the above recipe, I have even heard of people using just an overripe water melon, breaking the melon open and smearing the pulp on tree trunks.

My experience with sugaring is that it can be very variable in results and seems very dependant on the weather - still, humid nights are supposed to be the best. Patches that are regularly sugared are also supposed to become more attractive with time.

See also wine-roping for a similar technique of attracting moths.