The upper two bird stamps, issued in 1991, depict the Palau fruit dove (Ptilinopus pelewensis). As its name implies, it is endemic to Palau. It is also the country's national bird. It has no subspecies.

The lower bird stamp, issued in 1991 too, shows the Palau fantail (Rhipidura lepida), which is also endemic to Palau. It feeds on insects.

Issued by Belarus in 2025, the stamp depicts a pair of budgerigars (Melopsittacus undulatus). The species, a popular pet worldwide, is native to Australia.  Budgies feed on seeds, fruit and vegetation. The sex can be told apart by the colour of the ceres, which is blue in males.

Thank Olga for the lovely postcard!

 

Issued by Croatia in 2011, the middle stamp shows Eleonora's falcon (Falco eleonorae). I have written about this species in the past.

The common kingfisher (Alcedo atthis) has been presented in the past. Here, it is depicted on a 2025 stamp from Lithuania.

 Issued by Algeria in 2000, the stamps depict the European goldfinch (Carduelis carduelis), which has been featured in the past.