The two locations at which you have the best chance of spotting one of these nefarious creatures are at Mister Saint Leonard's mountain and in the forests around the Sylvern's Lake

Also known as Mount Saint Leonard, the mountain is to be found north of the town of Healesville, which is 64 km northeast of Melbourne. Follow St Leonards Rd from Healesville. After approximately 4km St Leonards Rd will veer to the left and become Myers Creek Rd. Travel 8.5km along Myers Creek Rd. Turn right at Monda Rd. Drive for 3.3km to the gate to the Monda track where you may park your car. To find the weepers, follow the instructions below which I was given by an experienced weeper hunter:

If monty weepers you would seek
Follow the path to the mountain's peak
Make your choice from two tall towers
Choose that which in the daylight hours
Will give direction and point the way
To show you where the weepers play
Remember; look up in the trees
Where your feet may be tangled, if you please

You will need to walk up the Monda track (1.5km) to the top of Saint Leonard’s mountain. Mister Saint Leonard’s tower will appear as a superficie in the form of a fire/communications tower and a wire fence will be in place to deter those of an over-zealous nature. There are marvellous views to be found from the lookout tower at the top of the mountain.
Note that the track is not wheelchair friendly and there are no toilet facilities available. Also; that four wheel drive may be required to traverse Monda Road during winter or extended periods of wet weather. You may need to check the Vic Forests website for road closures.

Known to most people as “Silvan Reservoir Park”, the Sylvern’s lake is located 40km east of Melbourne on Stonyford Rd, Silvan, off the Monbulk-Mt Evelyn Rd. The lake is surrounded by pleasant lawns and gardens, with barbecue and toilet facilities and a playground. There are wheelchair-friendly paths.  You may like to hunt for a monty weeper or two within the park grounds, or venture into the bush further along Stonyford Rd on one of the many tracks in the forest, where monty weepers are more likely to be found. Note, that for your protection from the Sylvern, whose lair lies at the base of the tower, access to the lake is prohibited and a fence is in place to prevent the foolhardy from risking the Sylvern’s wrath.
Park gates open 9am – 4.30pm (6.30pm daylight saving)

If monty weepers you would find
These three clues keep in mind:
Monty weepers do as they please, but always do it in the trees.
Monty weepers cannot fly, but you’ll always find them up on high.
Chocolate cake they think quite yum, but it is true too that they like gum. 

Well, as to when, I would suggest a day when the weather is fine, and the magnificent views from Mister Saint Leonard’s mountain can be enjoyed to their fullest. Winter may be the best time to go if you have a penchant for howling winds, heavy black clouds and rain, sleet or snow. Or if baking heat and bushfires are your thing, summer would suit you best. So ultimately it is up to you! Pack a picnic, wear your stoutest shoes and …Happy Hunting!