I have been hearing reviews regarding Al Areen Wildlife park for some time, but was somehow not able to make a plan myself- honestly because I assumed this place is for kids, and would not be of any interest for me. However, I was wrong, totally WRONG. The place is a must visit, for people belonging to all age groups, especially the ones with some interest in nature (and wildlife, of course).
Now since the weather in Bahrain is quite pleasant, it is the perfect time to plan a day out in Al Areen Wildlife Park and Reserve. Here is an overview about the place, combined with my personal experience and views:
The park is huge (no need to mention the exact dimensions is suppose), and is divided into animal preview, lake side with fountains and the green side.
After getting tickets from the counter, that cost 1 BD per adult, you enter the park, welcomed by the lush greenery and the lake, thus getting a very pleasant first impression.

Moving ahead, you may visit the walk-in Bird's Aviary, where several different species can be found in their natural habitat. 

The bus tours are offered for the animal preview section, as the area is huge and cannot be covered on foot (there are no separate charges for this tour). The guide will keep you updated about the animals that you are visiting, informing you about their origin and specialty. 

Then comes the Japanese Garden- a personal favorite. This small place, covered in green and properly maintained, is a must visit in Al Areen Wildlife Park and Reserve. With a clear shadow of Japanese architecture, the Japanese Garden is perfect for a small stay, a walk and of course, some beautiful clicks.

Al Areen Wildlife Park and Reserve will keep you occupied for the whole day- while there is a huge variety of animals, the place is also perfect for a small picnic/ day-out for friends and family members. The food court adjacent to the entrance would cater to your taste-buds, thus no need to worry about food while being there. 
Overall, the park and reserve is worth at least one visit, specially in this pleasant weather- and you can decide for yourself if it deserves a second visit!