The present study was conducted to investigate the eco-biology of two insect predator avian species and the effects of pesticides sprays on these predacious bird populations in Punjab, Pakistan. Data on ecology and other aspects of Bank Myna and Cattle Egret were collected from three districts of Central Punjab including Faisalabad (an industrial area with large effects of heavy metals due to usage of sewage water for irrigation & pesticides), Sargodha (with medium level of industries &pesticides use) and Mandi Bahauddin (no industry and low use ofpesticide). Two studysites were selected from each district and were labeled as availablenon-treated and treated. Specimens were collected to observe their gut contents and were analyzed to account for the prey and feeding niche. Major insect pests of crops were identified and listed from gut contents. Relative population density of useful birds was assessed and continuously monitored for population trends around the year. Breeding ecology of both predacious birds was studied to evaluate breeding success, mortality rate and to weigh up the effects of pesticides used and pollution. Breeding ecology, population dynamics and gut contents analysis were significantly (P ≤ 0.001; R2 ≥ 0.75) influenced by the use of pesticides. It was concluded that use of pesticides without studying their toxic effects is detrimental to these predacious birds. Blind sprays should be prohibited and alternatives should be adopted to conserve the predacious birds in order to achieve effective biological control. As an outcome of this study, specific ecological conditions in the form of “Wildlife Resort“ can be developed at farm level to attract these two species to roost there, breed there and to serve around as biological pest control agents.