My son attends a US university. He earned $1410 US working on campus and from an internship placement. Does this income need to be included on his Canadian tax return?

Canada requires you to report your "World Income", so "Yes", your son needs to claim all amounts he earned on his Canadian tax return. If he is required by the US to file a tax return to receive a refund of any taxes they may have withheld, he may be able to claim foreign tax credits against that income.

https://turbotax.intuit.ca/tips/using-the-united-states-canada-income-tax-treaty-to-reduce-double-taxation-6229