The Għadira Nature Reserve is (unfortunately) one of the few nature reserves in Malta. It is quite a small reserve, albeit it serves as shelter/home to some interesting flora and fauna. I discovered this place surprisingly late in life, and I was also surprised it didn't house a cache.  

Għadira Nature Reserve is open between September and May on Mondays & Thursdays 2pm-7pm, and on Saturdays 10am-4pm. Access is free of charge.

Għadira nature reserve is located in the north of Malta, on the outskirts of Mellieħa. The 7 hectare reserve comprises of brackish lake and saltmarsh habitat. Due to our dry climate in Malta, permanent areas of inland water are rare, making the Għadira wetlands are an extremely important habitat for birds and other wildlife. Around 140 species of migrating birds are seen annually. Most of the birds seen are migrants, stopping to rest and refuel before continuing their long migration journeys. Għadira Nature Reserve is a fully protected bird sanctuary, a Ramsar site, and a Special Area of Conservation within the EU Natura 2000 network.

The open waters of Għadira Nature Reserve attract migrant wading birds such as redshank, sandpipers and egrets. Along the trails look out for the sea daffodil, golden samphire and sea-lavender, as well as Mediterranean chameleons and rabbits hiding amongst the shrubs and trees. The call of the Zitting Cisticola can often be heard overhead, and resident moorhens are easy to spot across the pools. In the spring stop by to see Black-winged Stilts and Little Ringed Plover, both of which breed at the reserve. If you’re lucky you might even catch a migrating Eurasian Spoonbill or Greater Flamingostopping by to feed and rest!

(source)