Lake Tiilikka of the sandy shores
Tiilikkajärvi National Park was established to preserve wilderness-like lake, river and esker ecosystems, as well as, the open aapa bogs surrounding Lake Tiilikka. The lake is about 4 sq. km in size. The humus-filled River Itkonjoki flows into Lake Tiilikka after having passed through the parks mires. Lake Tiilikka has very few aquatic plants as the water is quite hard when it flows from the mires.
Some of the most typical water birds in the National Park are the Teal (Anas crecca) and the the Black-throated Diver (Gavia arctica). The most common waders are the Common Sandpiper (Tringa / Actitis hypoleucos) and the Wood Sandpiper (Tringa glareola). A Little Ringed Plover (Charadrius dubius) can often been seen on the sandy beaches. Visitors may also see structures and tracks made by beavers.
The scenery is dominated by low, narrow ridge capes covered by pines. One of these ridges divides Lake Tiilikka almost completely in two. White sandy beaches or water-smoothed stones outline the lake. The vegetation on the ridges is fragile and does not handle wear and tear well. For this reason visitors must stay on marked trails when crossing ridges.
Under one third of the land in the park is covered by forest, as mires are the predominant natural feature of the park. The majority of the forest is a dry pine forest. There is no lush forest here. The most common birds in the forests are the Willow Warbler (Phylloscopus trochilus), the Chaffinch (Fringilla coelebs), the Brambling (Fringilla montifringilla), the Spotted Flycatcher (Muscicapa striata), the Tree Pipit (Anthus trivialis) and the Redwing (Turdus iliacus).
Large open mires
Over two thirds of the park's area is mire. Tiilikkajärvi is a mire transition zone, where the features of northern and southern mires blend. For the most part the large mires in the park are open aapa bogs. The barren open mires are sliced in two from northwest to southeast by a line of ridges covered by dry forest.
On the edges of the open mires there are peat moss covered pine mires, with dry shrubs. The aapa bogs have a rich variety of birds. The most common bird there is the Yellow Wagtail (Motacilla flava). The waders which will most likely be seen in the park are the Wood Sandpiper (Tringa glareola) and the Whimbrel (Numenius phaeopus).