This study aims to provide the biological and geographical materials to identify the changes in population of Family Ardeidae included Egretta alba modesta, Egretta garzetta, Bubulcus ibis, and Nycticorax nycticorax and establish their conservation measurement in terms of the fragmented and deteriorated habitat by human development such as housing and park projects. Wonjucheon Stream was measured the highest species diversity since the survey site was relatively less interfered by the surrounding human beings showing lower disturbance elements. However, the closer the stream comes downstream, the more the artificial disturbance elements generate, confirming that the species better adapted to contamination grow in more density so that the species composition becomes simplified. It implies that feeding place as well as breeding-growing places is also more closely related to the changes in population structure and species composition of Family Ardeidae. The results of Family Ardeidae immigration in Taejang-dong, Wonju, among the other survey sites, revealed that a total of 231 came to the site in 2006; and 210 in 2011, showing more or less reduction in the population. In the mean while, Namyang-dong in Hwaseong City showed the continuous decrease in population number of Family Ardeidae with 135 before development and 60 during development, resulting in the number never growing but continuously narrowing over and over after development. As a result of surveying the number of Family Ardeidae that bred following the findings above, Taejang-dong in Wonju City had 4 species of Family Ardeidae being bred, however, showing the decrease in number of population from 998 in 2006 to 589 in 2011. Namyang-dong in Hwaseong was confirmed to have as many as 352 of the population in 2006 and 230 in 2008; after the deforestation on their habitat, they had not lived in the site any longer, suggesting that the development would significantly affect Family Ardeidae.