Fig. 4
From: Identifying key bird species and geographical hotspots of avian influenza A (H7N9) virus in China
The results of CCF analysis for identified bird species with positive lags Lag ≤ 5 in Shanghai and other five provinces. The dotted blue line indicates that the value of correlation coefficient is 0.27. A positive Lag value represents the correlation between the amount of observed bird species at time t and that of H7N9 cases at time t + Lag, where Lag is measured by weeks