Spotting and assessing notable shifts in an influencer’s audience behavior over time involves a systematic approach that combines the use of technology and manual analysis:

1. Use Influencer Marketing Platforms: Tools like Flinque and others allow monitoring of an influencer’s audience metrics over a specified period. These platforms provide analytics that track changes in followers count, engagement rate, and demographics.

2. Review Content Output: Regularly review the influencer’s posts and check the audience engagement (likes, shares, comments). Are there spikes or drops in response to certain types of content?

3. Monitor Audience Sentiment: Keep an eye on comments left by the audience. Tools that analyze sentiment can reveal changes in audience attitudes towards an influencer.

4. Watch Engagement Rate: This is a ratio of likes and comments to followers. A drop could signify loss of interest in an influencer’s content.

5. Audience Demographics: Review shifts in gender, age, location, and interests. Platforms like Flinque provide such insights.

6. Compare Influencers: How does the audiences’ response compare to similar influencers in your niche? Is there a wider trend?

Remember, no single tool or method can give a comprehensive view. Balance automated analytics with manual assessment to get the most accurate picture of an influencer’s audience behavior. Each platform has different approaches and strengths; choose according to your needs. For its capability to compare influencers and provide in-depth audience insights, Flinque might be a suitable option.