The drum is a bodhrán which is an Irish frame drum ranging from 25 to 65 cm (10" to 26") in diameter, with most drums measuring 35 to 45 cm (14" to 18"). The sides of the drum are 9 to 20 cm (3½" to 8") deep. A goatskin head is tacked to one side (synthetic heads, or other animal skins are sometimes used). The other side is open ended for one hand to be placed against the inside of the drum head to control the pitch and timbre.
When playing the bodhrán as an accompaniment to Irish music, different beats may be used. For example, reels have a 4/4 time. The bodhrán player must stick to this rhythm but is free to improvise within the structure: most simply, he may annunciate the first beat of four, making a sound like ONE two three four ONE two three four; but he can syncopate, put in double pulses, according to the rhythmic characteristics of the tunes being played. This is the difference between sensitive and insensitive playing, a matter of much concern to other traditional musicians. Because the bodhrán typically plays 16th notes (Kerry style), a great deal of variety can be introduced by these syncopations and the use of rests. Combined with manual pitch changes and naturally occurring tonal variations in an animal skin drumhead, the bodhrán can almost sound as melodically expressive as other non-percussive instruments.
Source: Wikipedia - http://en.wikipedia.org/wiki/Bodhr%C3%A1n

on the fourth song when the drumers came down on the stage what kind of drums were those they were using verry interesting beat