Here in this type of question we can use momentum conservation
It is because we can see there is no external force on the system
So we can use momentum conservation principle
[tex]m_1v_{1i} + m_2v_{2i} = m_1v_{1f} + m_2v_{2f}[/tex]
here we know that
[tex]m_1 = 2 kg[/tex]
[tex]v_{1i} = 6 m/s[/tex]
[tex]m_2 = 1 * 10^1 kg[/tex]
[tex]v_{2i} = 0[/tex]
now after bird sits on it then final speed of the both will be same
[tex]v_{2f} = v_{1f} = v m/s[/tex]
[tex]2*6 + 1*10^1 * 0 = (2 + 1* 10^1) * v[/tex]
[tex]12 = 12*v[/tex]
[tex]v = 1 m/s[/tex]
so final speed will be 1 m/s
