I am a parasitic plant, often found on grapevines, with a unique method of seed dispersal. My stems are often purplish or reddish, and my leaves are reduced to scales. What am I?

1. I lack chlorophyll and thus cannot photosynthesize.
2. I form haustoria to extract nutrients from my host.
3. My flowers are small and often yellowish or whitish.
4. Birds are involved in my seed dispersal.