
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given the hyperbola $\dfrac {x^{2}}{5}-y^{2}=1$ has its foci as the vertices of the ellipse $C$: $\dfrac {x^{2}}{a^{2}}+ \dfrac {y^{2}}{b^{2}}=1(a > b > 0)$, and the eccentricities of the ellipse and the hyperbola are reciprocal to each other.  
$(I)$ Find the equation of the ellipse $C$;  
$(II)$ Let point $M$ be on the ellipse $C$, and $|MN|= \dfrac {4 \sqrt {3}}{3}$. Denote the y-intercept of line $MN$ as $m$, find the maximum value of $m$.

Present the answer in LaTex format: \boxed{Your answer}
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